tag:blogger.com,1999:blog-91472233207397221882024-03-05T21:09:16.472-08:00A FIELD OF MUD AND BONE"The true value of any bonebed study rests not only in the eventual story told, but also in the breadth and quality of data that lie behind the narrative" -Raymond Rogers, <i>Bonebeds</i>Benjamin Scherzerhttp://www.blogger.com/profile/06017783834589973483noreply@blogger.comBlogger12125tag:blogger.com,1999:blog-9147223320739722188.post-88004962131176270262013-04-17T08:53:00.000-07:002013-04-17T08:53:25.118-07:00Why the Graboids from "Tremors" Totally Would Not Have Worked, and the One Thing They Got Right, Part II<span style="font-size: large;">We resume my
review of the “graboids,” giant carnivorous worms from the 1990 cult classic “<span style="color: red;"><a href="http://www.imdb.com/title/tt0100814/?ref_=ttqt_qt_tt" target="_blank">Tremors</a></span>.” My previous post ended midway through a lengthy
diatribe criticizing the flaws in their supposed fossorial lifestyle. I’m not
quite finished with the criticism, but I do have a few good words to say about
the monsters, and the movie as well. So, without further ado…</span><br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://tremors.wikia.com/wiki/Graboid" target="_blank"><br /><img border="0" height="364" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgUSlZVXZYmGcpbkEJPDwt-VUazNrZy3St4L5YvL4NcUY3donKvmij7DYd_xpyVVx1KFi-NXCt-On6XW9pmZceb4ZzK-OJZgWTzd7V5-wutlJbDGhKlQ3lrghzW3rUGs1hqux46wd7MdPE/s640/Graboid_tongues.jpg" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">"Miss me?"</td></tr>
</tbody></table>
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<b>Problem #3: Internal
rumblings</b></div>
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It is
established fairly early in the movie that graboids are blind*, and detect
and follow their prey via seismic waves (= vibrations) – entirely logical
adaptations for a burrowing organism. While this detection is shown to be quite
sensitive and spatially precise, it is not very discriminatory. Through the
course of the movie, graboids are attracted to not only to prey, but to a
hand shovel, pogo stick, tumbler, chest freezer, unmanned riding mower, running water, and
possibly a jackhammer. </div>
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<span style="font-size: x-small;">*Strangely,
later in the movie, the graboids supposedly learn that motor vehicles keep
their prey safe, and manage to locate and disable a pickup truck and SUV, even
though neither is running at the time….</span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijqqiOMiZgkBqNgeCvh11F7NwX8Joa_JyQVcnNI2TeJno_XEpbn8tCj5dtjXJQFnA8dXhtHCohhfOGMmX7gUJVkKd_31bkmIxXOWdJJyKu2WUhPRhVXsu8vVtxZoJAcRS1uMKPO5YjeeI/s1600/nevadamapthumb.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijqqiOMiZgkBqNgeCvh11F7NwX8Joa_JyQVcnNI2TeJno_XEpbn8tCj5dtjXJQFnA8dXhtHCohhfOGMmX7gUJVkKd_31bkmIxXOWdJJyKu2WUhPRhVXsu8vVtxZoJAcRS1uMKPO5YjeeI/s200/nevadamapthumb.jpg" width="130" /> <img border="0" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQQ-KkZQiiVZJeXfCA-YvSI62EPMFsiGJZ_BUkpG79u2tr688a3X3-cs_d9YsxNTCcSxHe49DoHuwNnWVM6cMrg-jwui5cZeV9atdIrZJ3mXxOkLrMuY64tnehNLrBxE1Cq7znTrz4qUg/s200/2012-10-11_1041.png" width="190" /></a></div>
But if this style
of prey detection is true, graboids have either extremely bad luck or a
terrible sense of direction. Nevada, where the movie takes place, is the <a href="http://crack.seismo.unr.edu/ep/nvguide/threat1.html" target="_blank">third most</a> seismically active state in the nation, just behind Alaska and California
(you may have heard about earthquakes in those two…). If you look at the geologic
map of Nevada to the top left (from <a href="http://geology.about.com/od/maps/ig/stategeomaps/NVgeomap.htm" target="_blank">here</a>), you may notice that mountain
ranges are arranged in parallel bands with an eerie resemblance to the stretch
marks on a pregnant woman’s belly (bottom left; from <a href="http://nelsonchow.hubpages.com/hub/Stretch-Marks-During-Pregnancy-and-Prevention" target="_blank">here</a>). This is not a coincidence – in CliffsNotes®-style
plate tectonics, the plate being subducted under the west coast (the one
ultimately responsible for the San Andreas Fault) is dragging and stretching the western United States
along with it, expanding Nevada to several times its original width. Inherent
to this is a lot of seismic activity. Graboids trying to pinpoint the footsteps
of a puny human amidst all the seismic background noise is akin to trying to
find a buzzing housefly in the middle of a <a href="http://www.youtube.com/watch?v=2YpOw8o34BM" target="_blank">dubstep</a> concert.</div>
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Incidentally,
the co-option of seismic waves by animals is not limited to science fiction.
Several modern organisms are suspected of using seismic waves for
communication, probably the most notable being the elephant. Elephants, both
Asian and African, appear to <span style="color: red;"><a href="http://phys.org/news4211.html" target="_blank">generate and detect low-frequency waves</a></span> for long-distance communication. Some <span style="color: red;"><a href="http://blogs.smithsonianmag.com/dinosaur/2011/02/how-parasaurolophus-set-the-mood/" target="_blank">paleontologists</a>
</span>have also hypothesized that hadrosaurids (duckbilled dinosaurs) may have
participated in similar communications, using their elaborate headgear as resonance
chambers.</div>
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<b><br /></b>
<b>So what’s
the good news?</b></div>
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Fortunately,
the producers of “Tremors” did manage to include one impressively accurate
feature on the graboids (possible unintentionally, but I’m willing to overlook
that). In several scenes, graboids display prominent finger-like or fringe-like
lateral projections. I assume these to be the gigantic equivalent of <a href="http://en.wikipedia.org/wiki/Seta" target="_blank">setae</a>:
miniature hair-like structures found on many organisms, including our <span style="color: red;"><a href="http://www.npr.org/templates/story/story.php?storyId=9105956" target="_blank">invasive</a> </span>friend the earthworm. In earthworms, these
structures are very small – even at the microscopic scale in the image below,
you may still believe I’m pulling your leg when I say the structures really are
there.</div>
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<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEga_4DV8buLCviWhMwQSDTGtp7lfmopzDwpNhdGMm_K_HqsC0ns8weEDpkbq6gOgyvsKJaV_HtP_8_qvoxnx_nuYqc30jsroKceuBBysu6hBj3yjXjX693iPk6dk1B2NI7ERazWnGfIY4M/s1600/5d9c5dde211f192601fceabab7cd6875.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="181" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEga_4DV8buLCviWhMwQSDTGtp7lfmopzDwpNhdGMm_K_HqsC0ns8weEDpkbq6gOgyvsKJaV_HtP_8_qvoxnx_nuYqc30jsroKceuBBysu6hBj3yjXjX693iPk6dk1B2NI7ERazWnGfIY4M/s400/5d9c5dde211f192601fceabab7cd6875.jpg" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">asknature.org/strategy/29204f007bb1d29b7c2f63a580fd7d4d</td></tr>
</tbody></table>
<br />
But they are
present, and damned effective. Earthworms use them to “grip” the soil and
assist with locomotion – an important trait for a cylindrical, slimy
invertebrate. They also help the earthworm resist attempts to remove it from the
ground - anyone who has ever tried to pull up earthworm probably learned that
even if you have the grip of a professional free-climber, the best you will end
up with is half an earthworm. Scale this trait up to a whale-sized worm, and very well-anchored organism would result. In fact, in a scene early in the
movie, one of a graboid’s “tongues” manages to clamp onto the axle of a pickup.
The pickup is able to get away after flooring the gas, but it only succeeds in
pulling the “tongue” out by its base, leaving the rest of the graboid likely in exactly the same position it started, albeit in much pain. </div>
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Unfortunately,
the graboids in the movie never fully utilize their extreme stubbornness.
Towards the end of the movie, the town’s survivors hatch a plan to escape on a
bulldozer – reflecting on the graboids’ previous motor vehicle destruction, one
of the characters says something along the lines of “[The bulldozer] weighs more than 30
tons. There's no way they could lift that!” Well, it turns out the graboids
wouldn’t need to bother. If setae can allow an earthworm to resist something
100,000 times its size, they sure as hell can allow a graboid to immobilize a
bulldozer. One graboid would simply need to bite down on the dozer and hold it
place, then patiently wait for the trapped prey to “jump ship”
(and the graboids are shown early in the film to do <a href="http://www.youtube.com/watch?v=CfAS7ONO8OU&list=PLE79F3F410DF4699E" target="_blank">just that</a>).</div>
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For the
record, I don’t mean to sound too critical of the movie – as I said, it is one
of my favorites. It effectively blends horror and comedy, portrayed Reba McEntire and the father
from “<span style="color: red;"><a href="http://www.imdb.com/title/tt0083413/?ref_=fn_al_tt_1" target="_blank">Family Ties</a></span>” as survivalist gun nuts, and
accurately depicted “bromance” decades before Judd Apatow wasted film on
nothing but two hours of hairy, pasty-white men waving their dongs at the
camera to bad 80’s pop music. But if the producers or writers had consulted with a
biologist (or, apparently, a bored paleontologist), they could have created a
rare good science/cult classic combination, and saved the bandwidth needed for
these last two blog posts.<br />
<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://drawception.com/viewgame/FjOC7QE4OA/earthworm-jim-fights-nazi-kittens/" target="_blank"><br /><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDxdMNevUp07vxT7pDF1Ydl7-xXeY5FXKiQ9_pe54ea5drsSFKmrlkCRrkjeKrZ_mjv-8Xq_Ju90sTEOzjBu4kYrKB1AdK_TzCyAVgClhQ6-4hskKZ4a6fCocaFM888qAaNrPr3kMsl2U/s1600/FjOC7QE4OA-8.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Although, considering what most of the internet is used for,<br />
perhaps that's not such a great loss after all...</td></tr>
</tbody></table>
<br /></div>
Benjamin Scherzerhttp://www.blogger.com/profile/06017783834589973483noreply@blogger.com0tag:blogger.com,1999:blog-9147223320739722188.post-49576318387988766682013-04-16T15:43:00.000-07:002013-04-16T17:30:10.564-07:00Why the Graboids from "Tremors" Totally Would Not Have Worked, and the One Thing They Got Right, Part I<br />
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<span style="font-size: large;">The move to
California has made its impact on my life, and consequently this blog. I give
my employer credit for keeping me busy, which severely limits blogging time. On
the other hand, it has given me ample exposure to Quaternary alluvium (Qal), and
much time to ruminate on this type of sediment. One of my most consistent
ruminations revolves around the monsters from one of my favorite movies - the
1990 cult classic “<span style="color: red;"><a href="http://www.imdb.com/title/tt0100814/?ref_=ttqt_qt_tt" target="_blank">Tremors</a></span>.” Unfortunately, my
armchair evaluations have led me to conclude the monsters, dubbed “graboids” in
the movie, would never work realistically. For this blog post, I will begin
explaining how I arrived at this conclusion…</span><br />
<br /></div>
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="http://monstermadnezz.blogspot.com/2010/11/graboid-movie-monster.html" style="margin-left: auto; margin-right: auto;" target="_blank"><img border="0" height="337" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVHfMI1_PnzWJ8giPM2iyyaOn8WmeRvRqzUppaS-CQJQWrM_F8MfgN1Q_T6Gr2HnWEb_-BeFr3cDwt53fQgaI_n68LCVJxzAkVUevo0SKoxmPWrwjc1OX9_drPt8q77mOj_lqydx8Lqkk/s640/Graboid.JPG" width="640" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><span style="font-size: small;">The monster of concern, in true 90's-era video quality</span><span style="font-size: x-small;">.</span></td></tr>
</tbody></table>
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<br /></div>
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<b>NOTE: In my
“research,” I tried to exclusively limit myself to data presented in the
original movie, and not any of the lame sequels or fan fiction. Apologies if any of the following criticisms are resolved in subsequent movies.</b></div>
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<o:p><br /></o:p></div>
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="http://cinemajunkyard.wordpress.com/2011/10/07/tremors-1990/" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;" target="_blank"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjIPI2KYcNeewb1KnbEprJ2OUen3S0a5hRvq9iv-QO4TteRp39mayD2xjvZgNgdYAs4Wv0nH95zywKgiejXBO6sfdPu4CTxL5kYlw5D9YKZVFPZJ-DgnLgHITrLTL3ipBSqS_2Nxxxyqek/s320/tremors_behind-the-scenes2.jpg" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">cinemajunkyard.wordpress.com/2011/10/07/tremors-1990/</td></tr>
</tbody></table>
For those
who have not seen the movie, the plot revolves around the denizens of a small, isolated,
rural Nevada town trying to escape the wrath of four giant carnivorous
subterranean worms. That’s not the best sell on my part, but it works on the
screen – I would recommend watching it for those that have not seen it. <span style="mso-spacerun: yes;"> </span><br />
<br />
First, some
background on the monsters: no specific dimensions are ever given for the graboids, but the picture to the left indicates they are around 2 m wide, and the
occasional full-body shot in the movie suggest they push 10 m in length. For
comparison, that is slightly larger than an orca (this will be important
later). Nearly all the necessary information about the graboids’ behavior is
nicely summarized in the following clip from
early in the movie, when “Old Fred” meets his demise:<br />
<br />
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<iframe allowfullscreen='allowfullscreen' webkitallowfullscreen='webkitallowfullscreen' mozallowfullscreen='mozallowfullscreen' width='320' height='266' src='https://www.youtube.com/embed/mbKEarx9CCs?feature=player_embedded' frameborder='0'></iframe></div>
<br />
As you can
see, graboids live and travel underground (technical term: fossorial
burrowers), and not very deeply - their arrival in the above clip disturbs a
scarecrow that is anchored into the ground by no more than a couple feet. Additionally,
throughout the movie, graboids are frequently shown to be traveling less than 1
m below the surface, especially when stalking or capturing prey. A key plot
point in the movie is the graboids can only travel through the Quaternary alluvium
– when one runs into a ~50 cm cement wall, it ends up killing itself through
blunt force trauma. They also capture their prey by pulling it underground as
Kevin Bacon wryly <span style="color: red;"><a href="http://www.youtube.com/watch?feature=player_detailpage&v=LwbFwVf8yoE&list=PLE79F3F410DF4699E#t=58s" target="_blank">observes</a></span> (warning: simulated horse mauling). In the movie they
are shown (or implied to) pull sheep, humans, horses, and even an entire
station wagon underground.<br />
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<br /></div>
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Second, some
background on the author: I am currently employed primarily as a
“paleontological field monitor,” meaning I watch construction, much of it in
Qal, for the disturbance of fossils. This presents the
opportunity for long periods of deep thinking, but not much else to envy. Conveniently,
much of the groundwork I have observed is comparable to what would be required
of a whale-sized fossorial organism, and I have arrived at two major flaws with
the graboids.</div>
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<br /></div>
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<b>Problem #1: No,
<i style="mso-bidi-font-style: normal;">you’re</i> a dense medium!</b></div>
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<br /></div>
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First off,
let’s return to that “fossorial” part. In contrast to the more familiar
terrestrial and arboreal (flying) animals that live and travel in air, and
aquatic organisms that live and travel in water, fossorial organisms spend at
least part of their lives in the soil. For the purposes of this discussion, we
will sidestep the strict definition of “soil,” and just keep in mind that the
majority of soil is loose rock grains. Forgivably, most of us are only familiar
with soil when it is in a unique, heavily disturbed state – after is has been
dug up and placed in a pile, or well-tilled and aerated in a garden. Under
these conditions, the grains have been separated and the soil is spatially
unconfined. But in its natural state, soil is under stress from the weight of
the soil above it, and confined by the soil surrounding it in all directions.
This causes grains to tightly compact, resulting in a heavy, dense medium. </div>
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<br /></div>
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For comparison:
the atmosphere through which we regularly move is .001 g/cm<sup>3</sup>. According
to casual conversations with soil scientists, undisturbed Qal like that in the movie is naturally 75 – 80% grains
by volume (rock = 2.7 g/cm<sup>3</sup>, for our sake). "Back of the envelope"
calculations suggest the soil itself would have a density of at least 2.3 g/cm<sup>3</sup>,
i.e. over <i style="mso-bidi-font-style: normal;">2000 times</i> denser than air*.
</div>
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<br /></div>
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<span style="font-size: x-small;">* For a good
“hands-on” example, pick up a bag of vacuum-packed coffee grounds at the
grocery. In that state, the contents are about 80% grounds by volume, and the
vacuum packaging simulates the confinement from surrounding sediment. Imagine
digging through something like that, but harder, and you have a good
approximation of a burrowing lifestyle.</span></div>
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<br /></div>
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQst6LscCEu_69EMIynDdk2h_hNDRsDH6kcy4rtqGEToI68BCqzAVM6GoJLI5fBnPCIB4FIwUvXvQmXH06NYEC7xlpyYVkOmW_7lvL09fRnIb5MHMwFuJr5S8-eZsqUkhaA3SJoyMU9io/s1600/Ratmolehumerus.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="270" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQst6LscCEu_69EMIynDdk2h_hNDRsDH6kcy4rtqGEToI68BCqzAVM6GoJLI5fBnPCIB4FIwUvXvQmXH06NYEC7xlpyYVkOmW_7lvL09fRnIb5MHMwFuJr5S8-eZsqUkhaA3SJoyMU9io/s320/Ratmolehumerus.jpg" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">ossamenta.dreamwidth.org/24900.html</td></tr>
</tbody></table>
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Needless to
say, unless an organism is microscopic, traveling through such a dense medium
places extraordinary demands on its body. For a classic example of this, look
no further than the image at the left – the bone
on the left is a rat humerus, and the bizarre-looking bone on the right is actually
the humerus of a similarly-sized common North American mole. Evolution has
forced it to extensively remodel itself to accommodate enormous arm muscles for
a lifetime of efficient digging. The adaptations of other digging organisms –
from the massive teeth and neck muscles of <a href="http://en.wikipedia.org/wiki/Bathyergidae" target="_blank">mole-rats</a> to the lethal claw of
badgers – are all testaments to the demands of living underground.
Consequently, fossorial organisms are relatively quite rare – if I were to spontaneously
ask you to name all the burrowing vertebrates you could think of, you would
probably list a sizeable percentage without trying too hard.</div>
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<br /></div>
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Part of the
reason for this rarity is that the extraordinary demands require extraordinary
fuel. A single mole or gopher can wreak a seemingly disproportionate amount of
havoc on your victory garden because is needs a lot of nutrition to move
through something 2000 times more challenging than a hurricane. And even the
best burrowers are comparatively painfully slow at subterranean locomotion – I was
unable to find estimates for how quickly various burrowing organisms can move
while underground, probably because it’s too slow to really warrant a velocity.
In contrast, graboids are shown to burrow at speeds faster than a sprinting
young adult male human, and travel dozens of kilometers (at least) over the
course of three days. And they are <i>whale</i>-sized.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjecJRlpANpRvD_vX68vcUe8a5BEg76RhzKni8K7OT1z_wjJFvulKgIuL8ANq_g2S53iKujb2suxwQbcw2Nf1Mc3ZcP4GSeB8DLJM0rV-_cpGTzg4zHtDvixMm1NpxaGEbTNJIQLP9pPik/s1600/P7310008.JPG" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjecJRlpANpRvD_vX68vcUe8a5BEg76RhzKni8K7OT1z_wjJFvulKgIuL8ANq_g2S53iKujb2suxwQbcw2Nf1Mc3ZcP4GSeB8DLJM0rV-_cpGTzg4zHtDvixMm1NpxaGEbTNJIQLP9pPik/s320/P7310008.JPG" width="320" /></a></div>
Again, for
comparison: the image to the left (traffic cone for
scale) shows auger bits used on a highway expansion project I monitored. The
auger excavated a 1.5 m-diameter tunnel, roughly equivalent to the width of the
graboids. But it took five 8-hour days, running on two 11,000 watt generators,
to excavate a 15 m-long tunnel. Now, 22,000 watts converts to 29.5 horsepower
(hp). In an interesting paper in 1993, Stevenson
and Wassersug calculated the upper limit of an actual workhorse’s power output
to be 14.9 hp, and that it could only last for a few seconds. If an organism could
double this theoretical maximum and maintain it for hours, it could
potentially burrow at 0.3 km/hr – definitely not enough to catch Kevin Bacon in
a dead sprint. To account for the activity exhibited in the movie, a single
graboid would have to possess magnitudes of order more power than any known
organism on the planet, and have a food source rich enough to fuel it. And
there were <i style="mso-bidi-font-style: normal;">four</i> of them. The handful
of people and livevstock ingested would not have been anywhere near enough fuel to
go around.</div>
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<br /></div>
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OK, I’m
willing to concede the graboids’ burrowing abilities are merely <i style="mso-bidi-font-style: normal;">highly implausible</i>, not impossible. One
of reasons I like the movie is because it doesn’t make the mistake common to many
science fiction movies of trying to explain too much. The origin of the graboids
is never determined, so for all we know, they could be aliens with an unknown,
exceptionally efficient fuel source – ultra-<span style="color: red;"><a href="http://en.wikipedia.org/wiki/Brown_adipose_tissue" target="_blank">brown fat</a></span>,
perhaps. But even if they came from another planet, the laws of physics are universal, which brings us to problem number two…</div>
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<b><br /></b></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
<b>Problem #2:
Aristotle, still relevant after all these years.</b></div>
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<br /></div>
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One other
thing you might notice about the fossorial organisms you named earlier is how
small many of them are – squirrel-sized burrowers are the norm. There’s good
reason for this for this – for any subterranean space excavated, the disturbed
soil has to be moved somewhere, and the less dirt to haul, the better. For
permanent or semi-permanent burrows and dens, this is a one-time hassle. But,
as discussed above, the graboids are shown to be constantly on the move – while hiding from one, a character comments “Doesn’t he have a home to go to?” But nowhere in the movie
are visible <span style="color: red;"><a href="http://www.welcomewildlife.com/?folder=pages/urban%20wildlife/other/earthworms" target="_blank">castings</a> </span>or spoils from the enormous
burrows the graboids must have excavated – note how in the above clip, Fred's remains are surrounded by a small halo only a few centimeters high. Even after pulling the
aforementioned station wagon underground, there is no station wagon-sized
volume of spoils to be seen – two characters only know a vehicle is underground
because of the still-active radio. </div>
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<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left; margin-right: 1em; text-align: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDHO1NELe2rnmSgl4110lFm9CW6KGHQkYqFxn72lzLkg1ubc0G5uYut18rHtuRMBWtNDR7Oge_YUqurY2M1RLQxjTTMphU5BOuWkgkQhFSY35l22x4xZWlvKVK6o4fFcnvDU2tonwi0uk/s1600/130301151806-06-sinkholes-0301-horizontal-gallery.jpg" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="180" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiDHO1NELe2rnmSgl4110lFm9CW6KGHQkYqFxn72lzLkg1ubc0G5uYut18rHtuRMBWtNDR7Oge_YUqurY2M1RLQxjTTMphU5BOuWkgkQhFSY35l22x4xZWlvKVK6o4fFcnvDU2tonwi0uk/s320/130301151806-06-sinkholes-0301-horizontal-gallery.jpg" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">cnn.com/2013/03/01/us/florida-sinkhole-explainer</td></tr>
</tbody></table>
This is not
just an aesthetic quibble – it is related to a notable problem with the
graboids’ unique mode of predation. In order the pull, say, Fred underground, a
graboid needs to excavate a Fred-sized hole directly underneath him, regardless
of how the excavated soil is dispatched. Problem is, this is one of those
instances where <i style="mso-bidi-font-style: normal;"><span style="color: red;"><a href="http://en.wikipedia.org/wiki/Horror_vacui" target="_blank">horror vacui</a></span></i><span style="color: red;"> </span>is very much true – an
excavated subterranean space is living on borrowed time. The weight of the soil
and sediment overlying such a space will cause it to ultimately collapse - we
see instances of this every day with <span style="color: red;"><a href="http://ga.water.usgs.gov/edu/sinkholes.html" target="_blank">sinkholes</a></span>. As
a prime example, the picture to the left shows not
only the start of a commuter’s very bad day, but what commonly happens when a
graboid-sized tunnel is situated too near the ground surface. The graboids in
the movie are consistently shown to be moving even nearer to the surface, yet
only rarely is there any detectable disturbance above ground, and never
anything noticeable to the doomed prey. </div>
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<br /></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in;">
Personally, I
believe this plot hole was intentionally “edited out” – there is at least one
scene where the actual ground (not a scaled-down set) is disturbed in a manner
consistent with a near-surface graboid. The subsequent disturbed earth is
carefully edited out of the movie, but the film crew would have unavoidably seen
the physical aftermath in real life. Furthermore, in one ironic, humorous scene, a
character experiences a brief moment of terror when his foot sinks into a
gopher burrow. Yet in other scenes, burrows hundreds of times larger are
actively excavated underneath a person, yet go unnoticed and remain sturdy
until the person is pulled under. I’ll sympathize with the producers not
wanting to foot the bill for renting a backhoe to simulate collapsed tunnels
for every attack scene, but I do fault them for trying to “sweep under the rug”
a fundamental flaw with their own monster’s lifestyle. </div>
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But wait,
we’re not done yet! And it isn’t all bad! But I’ve written
enough for one sitting. Look for "Part II," coming soon!<br />
<br />
<span style="font-size: x-small;">REFS</span><br />
<span style="font-size: x-small;"><br /></span>
<span style="font-size: x-small;">Stevenson, R. D., and Wassersug, R. J., 1993, Horsepower from a horse: Nature, v. 364, no. 6434, p. 195, </span><a href="http://dx.doi.org/10.1038%2F364195a0" target="_blank"><span style="font-size: x-small;">doi:10.1038/364195a0</span></a></div>
Benjamin Scherzerhttp://www.blogger.com/profile/06017783834589973483noreply@blogger.com0tag:blogger.com,1999:blog-9147223320739722188.post-6932711835640792012012-02-12T11:59:00.000-08:002012-02-12T12:48:02.559-08:00Observations in the Uinta<span style="font-size:130%;"><s><span style="font-family:georgia;">Followers</span></s> </span><span style="font-size:130%;"> <span style="font-family:times new roman;">Accidental visitors of</span> this blog may have noticed my trademark neglect has been a little higher than usual, but in this case I can justifiably blame it on my new job, which has eaten up more than its fair share of my free time. This new occupation has exposed me to the wonders of the Uinta Formation, a Middle Eocene (46.5 – 40 Ma; Prothero, 1996), predominantly fluvial, accumulation of sediment shed from the Uinta Mountains to the north (Stokes, 1986; Rasmussen et al., 1999; Townsend 2004). Specifically, my observations are based almost exclusively in the middle Wagonhound Member, but that’s probably only of interest to serious stratigraphers…</span><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-size:130%;"><br /></span></p> <a href="http://www.cardcow.com/116818/covered-wagon-dog-team-real-photos/"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 320px; height: 206px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5PJ7OG1JOTrYccqw8oCfpvOiv26YRcDanTj-l5JqIyufxEuWKkBVp6FODllgVQVgEdRKsVkvNVeL4wBWS7oM6PFvn-dWO1V97UEF9SVjFDe89kaebfs5v86PnKsORn-dg_RTkq-nCFwA/s320/card00536_fr.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5708345462158537778" /></a> <p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal" align="center"> <span style="font-size:85%;">Marmaduke has died of dysentery.</span></p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"> <strong>Part I: Known knowns</strong></p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><strong><br /></strong></p> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3wGzFz0IR5IbZPZcb4nF7rRA5JV-s-CS5hgeZQNfnhgtqLfT15-r1gpdSpawxyV43q91xm1G6Y6Y4zU0Y0m4XLiGoH7ao-ULE5VuBwHvbV7cSFS-dNvLj8_kKd_Lp5C5fAESAHzaB9MM/s1600/IMGP0123.JPG"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 320px; height: 240px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg3wGzFz0IR5IbZPZcb4nF7rRA5JV-s-CS5hgeZQNfnhgtqLfT15-r1gpdSpawxyV43q91xm1G6Y6Y4zU0Y0m4XLiGoH7ao-ULE5VuBwHvbV7cSFS-dNvLj8_kKd_Lp5C5fAESAHzaB9MM/s320/IMGP0123.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5708343657204883634" /></a>The Wagonhound Member (hereafter Uinta B) is composed almost exclusively of thick, trough cross-bedded sandstones, thick overbank fines, and thinner massive sandstones and siltstones, with the thick sandstones forming the most blatant outcrops. These same sandstones are also commonly afflicted with a feature that looks like old war wounds (see left). <p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><br /></p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><br /></p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><br /></p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><br /></p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><br /></p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><br /></p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"> This feature can be seen at many scales, from the very small:</p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><br /></p><div align="center"> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEin1lp6XTuJHXbM3LzT1t-oWdzA7PkfA9MNc7rLKF34hWyq1ba0kpV7-SrN4pSooHh8rSkWVJgDD7OdQ_SWqgWtHsOeCTqFq5aYtseFWNS2shxlrRwJxeShPJLinA32yNozlnrERWiZP9s/s1600/IMGP0552.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 320px; height: 240px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEin1lp6XTuJHXbM3LzT1t-oWdzA7PkfA9MNc7rLKF34hWyq1ba0kpV7-SrN4pSooHh8rSkWVJgDD7OdQ_SWqgWtHsOeCTqFq5aYtseFWNS2shxlrRwJxeShPJLinA32yNozlnrERWiZP9s/s320/IMGP0552.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5708344428896531282" /></a> </div><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><o:p> </o:p></p> <p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal">…to moderate and localized:</p> <p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><o:p> </o:p></p><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgoFpuPzVkNfmgGirr0OtSNf4OfVbV47S9TGrGO-3MdohlU_tr_V0eiu0UEK82Hq8vqdZXGR5vFKzaX91rB4EXbliskU__Twiwg5T5LDogINZmFB0IWCVnJI8yPOVcidxu4YL0suW-pQIM/s1600/IMGP0124.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 320px; height: 240px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgoFpuPzVkNfmgGirr0OtSNf4OfVbV47S9TGrGO-3MdohlU_tr_V0eiu0UEK82Hq8vqdZXGR5vFKzaX91rB4EXbliskU__Twiwg5T5LDogINZmFB0IWCVnJI8yPOVcidxu4YL0suW-pQIM/s320/IMGP0124.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5708344915085740866" /></a> <p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal">…to occupying an entire cliff face:</p> <p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><o:p> </o:p></p> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfzJRfLz6B56tPpIPDJSXAr5PNSGbsjeGQeO8L60E6hUHQy-F9T52uPLng5VWW1ZoU7aUh7ei76xA0EQa3CMhDWr-dSd7ZKcncXFwlSTJpFJ_1XZTdG9LXYrRo32YLQrJI1OPpXqGrEkE/s1600/IMGP0125.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 320px; height: 240px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfzJRfLz6B56tPpIPDJSXAr5PNSGbsjeGQeO8L60E6hUHQy-F9T52uPLng5VWW1ZoU7aUh7ei76xA0EQa3CMhDWr-dSd7ZKcncXFwlSTJpFJ_1XZTdG9LXYrRo32YLQrJI1OPpXqGrEkE/s320/IMGP0125.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5708345188541926210" /></a> <p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal">This is a geologic feature known as tafoni, a consequence of salt growth inside rocks. Water, either ground or meteoric, contains salts, and in a porous rock such as sandstone, when water in the pore spaces evaporates, it leaves behind salts which crystallize to a larger volume. This displaces grains and increases pore space, and any time additional water is introduced, the process starts over, and a larger void is created. (For a more detailed explanation, as well as appropriate references, I would suggest the excellent <a href="http://tafoni.com/Welcome.html">Tafoni</a> website.) The occurrence of tafoni in the Uinta B is not at all surprising, as signs of salt precipitate can be seen everywhere:<br /></p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><br /></p><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgA-bnbVGwqkO_kT7xbScH70xnNa4OM14gDpsvVg4hB6Z2vfWS2e8I_arsoyHyarlpQd0yEY5raF9c8FToi4n9Xui2H_I7rCZbLnycB_AyiUFnSeNs3Yjuiw5xyAKan6k3UCMoYbNFUwJA/s1600/IMGP0553.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 320px; height: 240px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgA-bnbVGwqkO_kT7xbScH70xnNa4OM14gDpsvVg4hB6Z2vfWS2e8I_arsoyHyarlpQd0yEY5raF9c8FToi4n9Xui2H_I7rCZbLnycB_AyiUFnSeNs3Yjuiw5xyAKan6k3UCMoYbNFUwJA/s320/IMGP0553.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5708346097504405922" /></a><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"> This feature has erroneously been attributed to fossil termite mounds in the past (J. Strauss, personal communication), which is <i style="mso-bidi-font-style: normal">so</i> wrong on many levels, the least of which being that this feature is most common in channel sandstones, and any termite colony that fancied placing their nests in an active stream channel would be quickly eliminated from the gene pool.</p> <p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><strong><br /></strong></p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><strong>Part II: Known unknowns</strong></p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><strong><br /></strong></p><p><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiszYfUJakJbhgKvXzs4DIhQO340av3nX6t0Rv-3yN7r_4o2XWzmb9A1qK6ex-9JcXzA5u_6t0WyiCG_Y7HTYm7kX0K-W7H0RWuU6srS3sbGzPxo8Hoki_9tISY-fAQDp-O5UVP-IUAnb4/s1600/IMGP0119ed.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 203px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiszYfUJakJbhgKvXzs4DIhQO340av3nX6t0Rv-3yN7r_4o2XWzmb9A1qK6ex-9JcXzA5u_6t0WyiCG_Y7HTYm7kX0K-W7H0RWuU6srS3sbGzPxo8Hoki_9tISY-fAQDp-O5UVP-IUAnb4/s320/IMGP0119ed.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5708348593435013698" /></a>Another common feature of the Uinta B is nodules, spherical to subspherical to elongate “balls” of well-cemented sediment which can often be found littering outcrops like an ancient bowling range (see left). Precisely what causes these nodules to form is unknown to me – in part, this is due to my own lack of reading on the subject, but several sources I’ve encountered seem to casually suggest that their formation might be unknown in general. I haven’t seen anything to suggest the nodules are formed by different sediment than their host material – as you can see in example in the lower left, the nodule is eroding at just the same rate as the surrounding rock. </p><p><br /></p><p><br /></p><p><br /></p><p><br /></p><p><br /></p><p>Additionally, in the example below (you may have to click on the picture for full size), you can see in the cross-section of an elongate nodule (L), the sediment is clearly the same cross-bedded sandstone found a few meters away in the same outcrop (R): </p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="mso-bidi-mso-bidi-theme-font:minor-latin;font-family:Calibri;"><o:p> </o:p></span></p> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhN_CeWCnLbxBQcOGnH_XgT3goCI2jF6LWVze0slAR0byGgqx5ToXxUxn-IIg2s6f77ZCcrmCzYVR6vdQymZldLbW6KKyhAiiKGhhuCTedUlRsiLKt_wBgYvgBRdQzzd9YJvU0Lh4sTeq8/s1600/IMGP0558edited.jpg"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 149px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhN_CeWCnLbxBQcOGnH_XgT3goCI2jF6LWVze0slAR0byGgqx5ToXxUxn-IIg2s6f77ZCcrmCzYVR6vdQymZldLbW6KKyhAiiKGhhuCTedUlRsiLKt_wBgYvgBRdQzzd9YJvU0Lh4sTeq8/s400/IMGP0558edited.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5708350232611162658" /></a> <p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-family:georgia;">Some nodules I have encountered have certainly hinted at the importance of a nucleation site, which, as evidenced by the mammal vertebra (L) and turtle shell fragment (R) below, can often be fossils themselves:</span></p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-family:georgia;"><br /></span></p><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnqCGDIHXN6QWQ33wscModvQUxwbtrFcpYcDyn38nIzYdtEjA7a96vwpHPwvWvbiuSAIIgB8MzrBh99gur2OfrGH9jN4zEIarz1iwzPb3B9jVdZ3fVnicmIEZ76IVfnUw1XhdNE1RyZAA/s1600/IMGP0113edited.jpg"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 149px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnqCGDIHXN6QWQ33wscModvQUxwbtrFcpYcDyn38nIzYdtEjA7a96vwpHPwvWvbiuSAIIgB8MzrBh99gur2OfrGH9jN4zEIarz1iwzPb3B9jVdZ3fVnicmIEZ76IVfnUw1XhdNE1RyZAA/s400/IMGP0113edited.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5708351307075726274" /></a><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-family:georgia;"><strong><br /></strong></span></p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-family:georgia;"><strong>Part III: Unknown unknowns</strong></span></p><span style="font-family:georgia;"> </span><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-family:georgia;">Tragically, the most intruiging thing I have discovered about the Uinta Formation was not in the field, but in the literature – the sedimentology and stratigraphy of the Uinta is woefully not understood, despite the impressive work of a few individuals (Townsend, 2004, Townsend et al., 2006; Murphey et al. 2011). Part of this is due to the complexity of the Uinta beds and host fossils (Walsh, 1996), but part is probably also due to interest in the Uinta only being recently reignited, thanks to a booming oil industry (in overviews of the Uinta Formation geology, publications between ca. 1930 and 1990 are usually sparse). For someone with time and energy to dedicate to the formation, there’s probably no shortage of geologic information to be uncovered. That won’t be me, ironically, as I will soon be moving out of the area. But that’s a subject for future posts…</span></p><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-family:georgia;"><br /></span></p><span style="font-family:georgia;"> </span><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><o:p><span style="font-family:georgia;"> </span></o:p></p><span style="font-family:georgia;"> </span><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-family:georgia;"><span style="font-size:78%;">REFS</span></span></p><span style="font-family:georgia;"><span style="font-size:78%;"> </span></span><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-family:georgia;"><span style="font-size:78%;">Murphey, P.C., Townsend, K.F.B., Friscia, A.R., and Evanoff, E. 2011. Paleontology and stratigraphy of the middle Eocene rock units in the Bridger and Uinta Basins, Wyoming and Utah, </span></span><i><span style="font-family:georgia;"><span style="font-size:78%;">in </span></span></i><span style="font-family:georgia;"><span style="font-size:78%;">Lee, J., and Evans, J.P., eds., Geologic Field Trips to the Basin and Range, Rocky Mountains, Snake River Plain, and Terranes of the U.S. Cordillera: Geological Society of America Field Guide 21, p. 125–166, doi:10.1130/2011.0021(06). (pdf <a href="http://www.rockymountainpaleontology.com/bridger/download_pubs/Murphey_et_al_2011.pdf">here</a>)</span></span></p><span style="font-size:78%;"> </span><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-size:78%;">Prothero, D.R. 1996. Magnetic stratigraphy and biostratigraphy of the Middle Eocene Uinta Formation, Uinta Basin, Utah, </span><i style="mso-bidi-font-style: normal"><span style="font-size:78%;">in</span></i><span style="font-size:78%;"> Prothero, D.R., and Emry, R.J., eds., The Terrestrial Eocene-Oligocene Transition in North America, Cambridge University Press, pp. 75-119. </span></p><span style="font-size:78%;"> </span><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-size:78%;">Rasmussen D.T., Conroy, G.C., Friscia, A.R., Townsend, K.E., and Kinkel, M.D. 1999. Mammals of the Middle Eocene Uinta Formation, </span><i style="mso-bidi-font-style:normal"><span style="font-size:78%;">in </span></i><span style="font-size:78%;">Gillette, D.E., Vertebrate Paleontology in Utah, Utah Geological Survey Miscellaneous Publication, 99-1, pp. 401-410.</span></p><span style="font-size:78%;"> </span><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-size:78%;">Stokes, W.L. 1986. Geology of Utah: Utah Museum of Natural History, University of Utah and Utah Geological and Mineral Survey, Department of Natural Resources.</span></p><span style="font-size:78%;"> </span><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-size:78%;">Townsend, K.E. 2004. Stratigraphy, paleoecology, and habitat change in the Middle Eocene of North America, unpublished dissertation, Washington University, 418 pp. </span></p><span style="font-size:78%;"> </span><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-size:78%;">Townsend, K.E., Friscia, A.R., and Rasmussen, D.T. 2006. Stratigraphic distribution of Upper Middle Eocene fossil vertebrate localities in the eastern Uinta Basin, Utah, with comments on Uintan biostratigraphy: The Mountain Geologist, v. 43, no. 2, p. 115-134.</span></p><span style="font-size:78%;"> </span><p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal"><span style="font-size:78%;">Walsh S.L., 1996. Middle Eocene mammalian faunas of San Diego County, California, </span><i style="mso-bidi-font-style:normal"><span style="font-size:78%;">in</span></i><span style="font-size:78%;"> Prothero, D.R., and Emry, R.J., The Terrestrial Eocene-Oligocene Transition in North America, Cambridge University Press, p. 75-119.</span> </p>Benjamin Scherzerhttp://www.blogger.com/profile/06017783834589973483noreply@blogger.com1tag:blogger.com,1999:blog-9147223320739722188.post-48110191900896372182011-08-19T15:16:00.000-07:002011-08-19T17:31:18.374-07:00Animals in a Well of Unified Silla<p><span style="font-size:130%;">For our latest entry, we switch gears both spatially and temporally. Specifically, we turn our heads to Korea, and focus on more recent, archeological deposits. During my most recent family trip to Korea, we stayed for a few days in the southeastern city of Gyeongju. While there, we made a mandatory trip to the <a href="http://gyeongju.museum.go.kr/eng/">Gyeongju National Museum</a>, which as luck would have it, is currently housing a special exhibition entitled “Animals in a Well of Unified Silla,” or, directly translated from the Korean, “Fell into a Well Silla Animals.”</span></p><p><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIPe-jYXdrGH1OVAxxdFh0mT5Ungb7FUYW0Fw0x3KvnSaJL_UYF9kPiyWxPLEAZ6NcfqrrqftYi_nKnLznWT27MgtE1WlrBnli6bmW5qTiUpO6qyF_AMKXT43fLwVYPW-08vkKqhTOohY/s1600/SewerHorse.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 320px; height: 213px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIPe-jYXdrGH1OVAxxdFh0mT5Ungb7FUYW0Fw0x3KvnSaJL_UYF9kPiyWxPLEAZ6NcfqrrqftYi_nKnLznWT27MgtE1WlrBnli6bmW5qTiUpO6qyF_AMKXT43fLwVYPW-08vkKqhTOohY/s320/SewerHorse.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5642697858500843442" /></a> </p><p class="MsoNormal" align="center"><span style="font-size:85%;">My preference is the latter.</span></p> <p class="MsoNormal">To clear up any possible misconceptions, “Unified Silla” refers to a time period, not any physical feature of the well. The Silla Kingdom (57 BCE – 935 CE) was one of the Three Kingdoms of Korea, during which Gyeongju was the capitol, so the present-day city is ground zero for Silla history. The contentiously-named “Unified Silla” occurred towards the end of the Silla (668 CE – 935 CE). </p> <p class="MsoNormal"><strong>The gory details</strong></p><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcnZaxcBwySQSBzv7QFkr2HNZb_gWcS86PaUqKK2ebo7c418FLTVoMCSmpDIj2aIw9xd4xnR6IVrSPQ8DtpZQ_7t3YcwAvFxJnso_0p-7oeQhmNLOcKxPf8BVdgDsJiBcLwye74bQB19k/s1600/well+diagram.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 179px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcnZaxcBwySQSBzv7QFkr2HNZb_gWcS86PaUqKK2ebo7c418FLTVoMCSmpDIj2aIw9xd4xnR6IVrSPQ8DtpZQ_7t3YcwAvFxJnso_0p-7oeQhmNLOcKxPf8BVdgDsJiBcLwye74bQB19k/s400/well+diagram.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5642699049654233138" /></a><p class="MsoNormal">(<em><strong>Note</strong>: All information provided after this point is from concise museum signs and Google-translated articles, so I cannot guarantee all information made the transition accurately.</em>) Fast-forward roughly a millennia, and a recent excavation of Unified Silla (ca. 810 CE) wells, roads, and fences uncovered one particularly interesting well full of archeological booty [1]. At or near the base of this 10 m well were a plethora of ceramic vessels and bones. Over the course of two years (1998-2000) [2], over 2300 NISP (“pieces” [3]) were excavated, representing taxa including, but limited to: dog, cat, cattle, horse, deer, wild boar, rabbit, mole, mouse, ducks, crow, pheasant, thrush, falcon, snake, frog, shark, puffer fish, cod, mullet, whiting, mackerel, carp, bream, and probably most interesting, a 10-yr old human child [1][4]. A nice illustration of the well is given in unfortunately reduced size to the left [1]:</p> <p class="MsoNormal">A number of these bones have been nicely prepared and placed on display in the exhibit. Just looking at the displays provides some taphonomic information, such as the difference between the near-complete representation of cat and dog elements (below) versus some taxa (crow, Korean Water Deer) represented by just one or two elements. (<em><strong>Note again</strong>: apologies for pictures that are far from scientific quality – they were taken while walking through a busy, crowded museum.</em>) </p><p class="MsoNormal">
<br /></p><p class="MsoNormal">
<br /></p> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqF5X7KyqGcn1xhvp0mPHFxbt2ln-whDPGICLG7a-OftzoHuvLg6h6tU59S5w7LEQDcF_ouk3szytEFp94crnJDHpFq-XfS1brTujseI4N1m7wW3tSF3GXxJK_ZGWq0a2-mrRl51C3RLQ/s1600/IMG_9411.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqF5X7KyqGcn1xhvp0mPHFxbt2ln-whDPGICLG7a-OftzoHuvLg6h6tU59S5w7LEQDcF_ouk3szytEFp94crnJDHpFq-XfS1brTujseI4N1m7wW3tSF3GXxJK_ZGWq0a2-mrRl51C3RLQ/s400/IMG_9411.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5642700110970652818" /></a>
<br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgh78ayhRIQG6uOFlPA-Jo1E0QtpCzSCMn6dI8Ye3RdNz9uHt1s9MElDXQxZlToNoODY5C63fcLsnYzIpqKxCyXm_4b1r5PkZtXDUeXUZ7L15dnvwh1oWfY_ujpTFuODQHS-oZvBq834do/s1600/IMG_9410.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgh78ayhRIQG6uOFlPA-Jo1E0QtpCzSCMn6dI8Ye3RdNz9uHt1s9MElDXQxZlToNoODY5C63fcLsnYzIpqKxCyXm_4b1r5PkZtXDUeXUZ7L15dnvwh1oWfY_ujpTFuODQHS-oZvBq834do/s400/IMG_9410.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5642699972137777762" /></a> <p class="MsoNormal">Many of the elements also exhibited what appeared to represent wet rot, a poorly-understood corrosion-like modification of epiphyses and spongy bone in element with prolonged exposure to wet or moist conditions (Andrews and Cook, 1985; Andrews, 1995). This can be seen in the vertebrae and epiphyses of the cow elements below:</p> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNlG1PDdABm_EFzUsrTnsz52rj3NJ10qz8J_yTYmYQb8xO8GAyB6DlcnY7RiE41Uor2T6dSh1Lb5U8eoXqpnQybGCYHJGwXvryEkSzwWlEgYVJfcYYXGbDWJ8vDG6qN_EIHQT8Ah5rdbA/s1600/IMG_9417.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNlG1PDdABm_EFzUsrTnsz52rj3NJ10qz8J_yTYmYQb8xO8GAyB6DlcnY7RiE41Uor2T6dSh1Lb5U8eoXqpnQybGCYHJGwXvryEkSzwWlEgYVJfcYYXGbDWJ8vDG6qN_EIHQT8Ah5rdbA/s400/IMG_9417.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5642700642049364114" /></a>
<br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkXPRhJpDq5rrHNFYZR5lm2FheH6aoxbvbyMB2T64GikVhenHsrml9aMUdKpzPi_IJnLRqQhWjryMSCX4RQZuSfZzWMnabwEjRlm-2uKCaouaNX5AWX8gQqrwLY6EXv9OLVEBEjO2xecE/s1600/IMG_9414.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgkXPRhJpDq5rrHNFYZR5lm2FheH6aoxbvbyMB2T64GikVhenHsrml9aMUdKpzPi_IJnLRqQhWjryMSCX4RQZuSfZzWMnabwEjRlm-2uKCaouaNX5AWX8gQqrwLY6EXv9OLVEBEjO2xecE/s400/IMG_9414.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5642700513408835970" /></a> <p class="MsoNormal">Also in the cow element display, the rib shafts showed a form of modification that I have never seen before:</p> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglvUAw9RXKpwj1AFkhuGtcGRuX9jR6wHXxENDLl2Kva4AtuAJYyGH2hLYrEMaGpjQ9m_s5k1TeCz2YJv2-ayTsSNzB8xIWh56sC1-HTaQkBH1QmiLbbrB5Bz_zUdmfB4P6ZFt13ijtWg0/s1600/IMG_9418.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 300px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEglvUAw9RXKpwj1AFkhuGtcGRuX9jR6wHXxENDLl2Kva4AtuAJYyGH2hLYrEMaGpjQ9m_s5k1TeCz2YJv2-ayTsSNzB8xIWh56sC1-HTaQkBH1QmiLbbrB5Bz_zUdmfB4P6ZFt13ijtWg0/s400/IMG_9418.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5642701094582115122" /></a>
<br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgeWYfVF00-RiP8OaTAx9TpWClULIfF_3hjI8weeyON8URsqwn_g4pCRkuzYXvnf1at2PDuImvS7gDTzffCB3pJrM05zhcVH7hQWcqp27fw9H-MUkeUBUKsPpBlsPY17r-KRZEOkoV_T44/s1600/IMG_9415.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 300px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgeWYfVF00-RiP8OaTAx9TpWClULIfF_3hjI8weeyON8URsqwn_g4pCRkuzYXvnf1at2PDuImvS7gDTzffCB3pJrM05zhcVH7hQWcqp27fw9H-MUkeUBUKsPpBlsPY17r-KRZEOkoV_T44/s400/IMG_9415.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5642700929834695986" /></a> <p class="MsoNormal" align="center"><span style="font-size:85%;">I invite anyone to school me on this phenomenon…</span></p> <p class="MsoNormal"><strong>So how did it all get there?</strong></p> <p class="MsoNormal">There is little doubt the material in the well was artificially introduced. Nearly all the material is concentrated in the lower 2.5 m, with the very base of the deposit almost entirely ceramic vessels referred to as “earthquake spheres,” and the top of the deposits capped with stamped tile [4]. This suggests all the material was placed at the bottom of the well at one time [1], perhaps for “purification” [4]. There is the possibility that some (perhaps most) of the elements from the subterraneous critters (rodents, moles) may have been naturally introduced, but this can’t be tested without further data. Incidentally, for those concerned about dead animals at the bottom of a water source, it turns out that cold, stagnant water actually does a decent job of hindering decomposition. Besides, just about any natural body of water will have dead animals floating in it.</p> <p class="MsoNormal">The inclusion of the child is also the subject of much speculation; one hypothesis suggests he or she may have been victim of drowning, subsequently offered as a sacrifice [1] [4]. </p><a href="http://itallhappensinthedark.wordpress.com/2010/11/07/i-have-a-deadline/" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 320px; height: 182px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhfKjCJ6QLLoEnDj4jtpz4p6IwTBunovSMIbDKAZDwotihojB65FMkdxTSS8wlPNV0eU4nvrv3rpYBhB5JXodPhlWLKQFwmOaZG2RwHuqyzLAdGw-sLFNWnVA4rFwI9Pph9wOUM5iUPYb4/s320/ringu8.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5642701728608068530" /></a><p class="MsoNormal" align="center"><span style="font-size:85%;">Other hypotheses lack scientific rigor...</span></p><p class="MsoNormal">Hopefully, there will be more concrete explanations soon – allegedly, there is to be a professional publication on the excavation before the end of the year [3].</p><p class="MsoNormal">
<br /></p><p class="MsoNormal"><span style="font-size:78%;">REFS</span></p><p class="MsoNormal"><span style="font-size:78%;">1. <a href="http://translate.google.com/translate?hl=en&sl=ko&u=http://www.segye.com/Articles/News/Culture/Article.asp%3Faid%3D20110603002468%26cid%3D0101050700000%26subctg1%3D07%26subctg2%3D00&ei=59VCTr6wJufZiAKCtsGWBQ&sa=X&oi=translate&ct=result&resnum=1&ved=0CCQQ7gEwAA&prev=/search%3Fq%3D%25EC%259A%25B0%25EB%25AC%25BC%25EC%2597%2590%2B%25EB%25B9%25A0%25EC%25A7%2584%2B%25ED%2586%25B5%25EC%259D%25BC%25EC%258B%25A0%25EB%259D%25BC%2B%25EB%258F%2599%25EB%25AC%25BC%25EB%2593%25A4%26hl%3Den%26safe%3Doff%26sa%3DG%26biw%3D1366%26bih%3D667%26prmd%3Divns">Gyeongju National Museum exhibition...</a></span></p><p class="MsoNormal"><span style="font-size:78%;">2. <a href="http://translate.google.com/translate?hl=en&sl=ko&u=http://blog.daum.net/kinhj4801/15960426&ei=59VCTr6wJufZiAKCtsGWBQ&sa=X&oi=translate&ct=result&resnum=2&ved=0CC0Q7gEwAQ&prev=/search%3Fq%3D%25EC%259A%25B0%25EB%25AC%25BC%25EC%2597%2590%2B%25EB%25B9%25A0%25EC%25A7%2584%2B%25ED%2586%25B5%25EC%259D%25BC%25EC%258B%25A0%25EB%259D%25BC%2B%25EB%258F%2599%25EB%25AC%25BC%25EB%2593%25A4%26hl%3Den%26safe%3Doff%26sa%3DG%26biw%3D1366%26bih%3D667%26prmd%3Divns">"Fell into a well Silla animals' exhibition</a></span></p><p class="MsoNormal"><span style="font-size:78%;">3. <a href="http://translate.google.com/translate?hl=en&sl=ko&u=http://boomup.chosun.com/site/data/html_dir/2011/06/04/2011060400559.html&ei=59VCTr6wJufZiAKCtsGWBQ&sa=X&oi=translate&ct=result&resnum=3&ved=0CDUQ7gEwAg&prev=/search%3Fq%3D%25EC%259A%25B0%25EB%25AC%25BC%25EC%2597%2590%2B%25EB%25B9%25A0%25EC%25A7%2584%2B%25ED%2586%25B5%25EC%259D%25BC%25EC%258B%25A0%25EB%259D%25BC%2B%25EB%258F%2599%25EB%25AC%25BC%25EB%2593%25A4%26hl%3Den%26safe%3Doff%26sa%3DG%26biw%3D1366%26bih%3D667%26prmd%3Divns">Gyeongju museum fell into a well Silla animals' exhibition</a></span></p><p class="MsoNormal"><span style="font-size:78%;">4. <a href="http://translate.google.com/translate?hl=en&sl=ko&u=http://www.srbsm.co.kr/news/articleView.html%3Fidxno%3D18754&ei=59VCTr6wJufZiAKCtsGWBQ&sa=X&oi=translate&ct=result&resnum=5&ved=0CEcQ7gEwBA&prev=/search%3Fq%3D%25EC%259A%25B0%25EB%25AC%25BC%25EC%2597%2590%2B%25EB%25B9%25A0%25EC%25A7%2584%2B%25ED%2586%25B5%25EC%259D%25BC%25EC%258B%25A0%25EB%259D%25BC%2B%25EB%258F%2599%25EB%25AC%25BC%25EB%2593%25A4%26hl%3Den%26safe%3Doff%26sa%3DG%26biw%3D1366%26bih%3D667%26prmd%3Divns">Gyeongju Museum exhibition "fell into a well Silla Animals' prepared</a></span></p><p class="MsoNormal"><span style="font-size:78%;">ANDREWS, P., 1995, Experiments in taphonomy: Journal of Archaeological Science, v. 22, p. 147–153.</span></p><p class="MsoNormal"><span style="font-size:78%;">ANDREWS, P., and COOK, J., 1985, Natural modifications to bones in a temperate setting: Man (New Series), v. 20, p. 675–691.
<br /></span></p>Benjamin Scherzerhttp://www.blogger.com/profile/06017783834589973483noreply@blogger.com0tag:blogger.com,1999:blog-9147223320739722188.post-27503190928906706172011-03-26T17:36:00.000-07:002011-05-03T17:45:45.884-07:00Probably the Worst Healed Fracture I've Seen<p class="MsoNormal"><span style="font-size:130%;"><strong>Update: </strong></span><span style="font-size:130%;">Thanks to reader Mark'o Plenty for pointing out that the femur discussed below is, in fact, clearly avian. And shame on me for blindly assuming it was mammal and never thinking otherwise. Fortunately, this narrows down the list of victims - for a femur that size, the only real likely candidate out here would be a Wild Turkey (<em>Meleagris gallopavo</em>). This would also greatly narrow the list of culprits responsible for the break - most likely, a motor vehicle is responsible, as the galliformes in this area have near-suicidal tendencies with respect to the highways (Scherzer and Peck, personal observation). </span><span style="font-size:130%;"><br /></span></p><p class="MsoNormal"><span style="font-size:100%;">After subjecting this blog to what admittedly may qualify as criminal neglect, I return to the business of blogging, with a rather morbid “welcome back” post. I’ve been volunteering at local museum, and recently made an interesting recent discovery in the bone seen here:</span></p><p class="MsoNormal"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-Xj6kQ5mrpMvDYzCrN6LXRdiaKwvEpkoTSECI-63llO4chVpw3ajXNemXgy4StKSZBDZxXm9dS5VYk3enn_xtCExx__9fMrEmVA_eBzE6c7eEorYLhnG6wogT-x3SRavfj9uCx2qyytQ/s1600/image1.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 274px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-Xj6kQ5mrpMvDYzCrN6LXRdiaKwvEpkoTSECI-63llO4chVpw3ajXNemXgy4StKSZBDZxXm9dS5VYk3enn_xtCExx__9fMrEmVA_eBzE6c7eEorYLhnG6wogT-x3SRavfj9uCx2qyytQ/s400/image1.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5588552602784896562" /></a> That’s the femur of a small mammal – proximal end on the left, distal on the left, lateral side facing the camera - and it is abundantly clear that for a good portion of its life, that mammal was never having a good day. This femur experienced a complete fracture of the shaft – you can see a little window into the marrow cavity at the bottom – which significantly offset the bone, but the animal amazingly survived, and the bone healed. You can see the mass of regrowth where the bone healed along the shaft in the image above, and in more detail below. When examining the picture below, you should also make note of the femoral head (arrow) for later discussion:</p> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVQMJxVq0CoSb-5BPoZY4gCtb17bDRRBh6YNMM8bzTihv3fAppqz99-9xnEsQY74rAXg4Ddp-XwiAplFciGAruExd-LebHBap2wlvxt0FyhAx-LF8OAQKt5XBq3GOs3EtwcM5-wIuN1qY/s1600/image3edit.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 256px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVQMJxVq0CoSb-5BPoZY4gCtb17bDRRBh6YNMM8bzTihv3fAppqz99-9xnEsQY74rAXg4Ddp-XwiAplFciGAruExd-LebHBap2wlvxt0FyhAx-LF8OAQKt5XBq3GOs3EtwcM5-wIuN1qY/s400/image3edit.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5588552995101459362" /></a> <p class="MsoNormal"><o:p> </o:p></p> <p class="MsoNormal"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhykGdQRN_b29CmuusyJttpwU-2AZ8TmVeQu9c_X4trH_FgYCtv-INjRHL2AjZ1oNIYqq2S6z-UeZTbd1msCdsLNhzQh5HLDxM9njcF8QrpdLWw8d8FExxVujBpzt0OnX4pnfs45KDeQj0/s1600/A00259F01.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 99px; height: 200px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhykGdQRN_b29CmuusyJttpwU-2AZ8TmVeQu9c_X4trH_FgYCtv-INjRHL2AjZ1oNIYqq2S6z-UeZTbd1msCdsLNhzQh5HLDxM9njcF8QrpdLWw8d8FExxVujBpzt0OnX4pnfs45KDeQj0/s200/A00259F01.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5588553918526943458" /></a> The original length of the femur was 90 cm, and following the distortion, this was reduced to a little less than 75 cm, a reduction of almost 20% of the bone length. To put this in perspective, this would be like taking the thigh of the average American adult male (5’ 11”) and shortening it by roughly 3”. The image at left (from <a href="http://orthoinfo.aaos.org/topic.cfm?topic=a00259">here</a>) is probably a good comparison. You may also note some offsetting of the distal epiphysis, perhaps the result of crushing associated with the fracturing of the shaft. This damage to the epiphysis is seen in more detail in the image below:</p><p class="MsoNormal"><br /></p><p class="MsoNormal"><br /></p> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg-U5HQ_MK4fYm43DVqJ08-W2JAcrkXDekQxmGfxog3l0S2vQ1KrMHg07NWumX030l56Gb0Y9Jz0XqXkA9HcnMpYlX3jTVD0yqnwlUHz4Yxm-PfK6ntk3UU8e-pIm-Fb0VKfhu-zycrziM/s1600/image5.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 248px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg-U5HQ_MK4fYm43DVqJ08-W2JAcrkXDekQxmGfxog3l0S2vQ1KrMHg07NWumX030l56Gb0Y9Jz0XqXkA9HcnMpYlX3jTVD0yqnwlUHz4Yxm-PfK6ntk3UU8e-pIm-Fb0VKfhu-zycrziM/s400/image5.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5588553406644496114" /></a> <p class="MsoNormal"><o:p> </o:p></p> <p class="MsoNormal"><strong><span style="font-size:130%;"><br /></span></strong></p><p class="MsoNormal"><strong><span style="font-size:100%;">So who was the victim?</span></strong></p> <p class="MsoNormal"><o:p> </o:p></p> <p class="MsoNormal">One might naturally wonder what small mammal of Eastern Montana is stoic enough to put the <a href="http://www.youtube.com/watch?v=c81bcjyfn6U">Honey Badger</a> to shame. Unfortunately, the damage to the femur seems to have inflicted some side effects that hinder proper identification. Based solely on gross osteology and original length, I was able to narrow down six possible taxa with the help of Wolniewicz’s field guide of mammal bones (2004): Virginia Opossum (<i style="mso-bidi-font-style: normal">Didelphis virginiana</i>), Swift Fox (<i style="mso-bidi-font-style: normal">Vulpes velox</i>)*, Domestic cat (<i style="mso-bidi-font-style:normal">Felis catus</i>), Bobcat (<i style="mso-bidi-font-style:normal">Lynx rufus</i>), Coyote (<i style="mso-bidi-font-style:normal">Canis latrans</i>), and Domestic Dog (<i style="mso-bidi-font-style:normal">Canis lupus familiaris</i>)**.</p> <p class="MsoNormal"><o:p> </o:p></p> <p class="MsoNormal"><span style="font-size:85%;">* Wolniewicz only provided images of Grey Fox (</span><i style="mso-bidi-font-style:normal"><span style="font-size:85%;">Urocyon cinereoargenteus</span></i><span style="font-size:85%;">) and Red Fox (</span><i style="mso-bidi-font-style:normal"><span style="font-size:85%;">Vulpes vulpes</span></i><span style="font-size:85%;">), but from my understanding, their ranges do not include Eastern Montana, where they are replaced by the Swift Fox, so I made an educated deduction.</span></p><span style="font-size:85%;"> </span><p class="MsoNormal"><o:p><span style="font-size:85%;"> </span></o:p></p><span style="font-size:85%;"> </span><p class="MsoNormal"><span style="font-size:85%;">** Neither did he include Domestic Dog or Grey Wolf (</span><i style="mso-bidi-font-style:normal"><span style="font-size:85%;">Canis lupus</span></i><span style="font-size:85%;">), but considering the resemblance of the femur to that of the Grey and Red Fox, I figured it was prudent to include the Domestic Dog as a possibility.</span></p> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi94JWm5cVIvVtJokKpfG2inj6DxY0R5a87oX8vB-Tbx9_c3G3E9jDfOBlUT0-E_d4O7gXMXOVxHrUr3_t1jKW9fTKGmlxogwSXNCdwnM_L8ytf0roJ_OUVlb2AACe8ZX_2lVqfH0laLdw/s1600/image2.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 209px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi94JWm5cVIvVtJokKpfG2inj6DxY0R5a87oX8vB-Tbx9_c3G3E9jDfOBlUT0-E_d4O7gXMXOVxHrUr3_t1jKW9fTKGmlxogwSXNCdwnM_L8ytf0roJ_OUVlb2AACe8ZX_2lVqfH0laLdw/s320/image2.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5588557581547052882" /></a> <p class="MsoNormal"><o:p> </o:p></p> <p class="MsoNormal">But then a visible problem arose - if you look at the femur dorsoventrally (at left), the mediolateral offsetting from the fracture seems relatively minor, hinting that the animal may have tried to use the limb following healing. <span style="mso-spacerun:yes"> </span>But closer inspection of the proximal end suggests otherwise. The femoral head pointed out earlier (and visible in the top left of the image to the left), appears abnormally small, as can be seen by comparing it to the femoral head of some of the possible taxa:</p> <p class="MsoNormal"><o:p> </o:p></p> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhy3-cPC_e_4ipF0jLnw05nVLoJRoLhYSFhRI7f0e4fd8pEdZIsSu-6GLuUISM5XHQqcGAn2VX2_KRDk_23FcvBdsMyzEpuK5eAmhxM85IJi7Mf42M3QhYDyA3u8oaughs1UAg7aCsDlOA/s1600/comp2.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 100px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhy3-cPC_e_4ipF0jLnw05nVLoJRoLhYSFhRI7f0e4fd8pEdZIsSu-6GLuUISM5XHQqcGAn2VX2_KRDk_23FcvBdsMyzEpuK5eAmhxM85IJi7Mf42M3QhYDyA3u8oaughs1UAg7aCsDlOA/s400/comp2.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5588554818099267666" /></a> <p class="MsoNormal"><o:p> </o:p></p> <p class="MsoNormal"><span style="font-size:85%;"> (L to R) Domestic Cat, Bobcat, Coyote, Opossum. All to relative scale, all posterior view, </span><span style="font-size:85%;">femoral head at upper right. Ignore the lines. From Wolniewicz (2004).</span></p> <p class="MsoNormal"><o:p> </o:p></p> <p class="MsoNormal"><br /></p><p class="MsoNormal">In addition, all three trochanters (greater, lesser, and third) are practically absent. I noticed what appear to be rodent gnaw marks where the greater trochanter should be, but the lesser and third trochanters just plain aren’t there. This suggests the animal did not place weight on damaged limb after all, causing the associated muscles, and their respective trochanters, to atrophy as a result. This is good news for some of the taxa that were originally excluded due to their large size, namely the Bobcat and Coyote. A 90 cm femur is unlikely to come from an adult member of either of these taxa, and the fused epiphyses indicated this femur was not from a juvenile. However, a juvenile individual could have broken the femur, and the subsequent neglect would have left it matured but undersized (which is not uncommon). But this is bad news for me, since these trochanters are very useful in identifying taxa, so I was left with a short hand (no pun intended). One tantalizing clue that remains in an unusual groove in the lateral condyle (seen below). This groove is not diagnostic of any North American mammal I’m familiar with, and I didn’t see the feature in any of the images from Wolniewicz (2004). But I would love to hear I’m wrong***.</p> <p class="MsoNormal"><o:p> </o:p></p> <p class="MsoNormal"><span style="font-size:85%;">***Anyone? Anyone?</span></p> <a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXu3AgdtBSgXmU-PBnMahKO9x_b-xkoN0bfUUqszv6zQdprDCAiPLnSx3rQ3XcI7YQ_m_QT-qoUvwV8Xch4zTH6TdvAh6kXNyRoKsUifaTjtBtQAIG89JLoJJuAiapshOR4n8D3fHxccc/s1600/image4edit.jpg" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 356px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjXu3AgdtBSgXmU-PBnMahKO9x_b-xkoN0bfUUqszv6zQdprDCAiPLnSx3rQ3XcI7YQ_m_QT-qoUvwV8Xch4zTH6TdvAh6kXNyRoKsUifaTjtBtQAIG89JLoJJuAiapshOR4n8D3fHxccc/s400/image4edit.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5588555624143880210" /></a> <p class="MsoNormal"><o:p> </o:p></p> <p class="MsoNormal"><strong><span style="font-size:130%;"><br /></span></strong></p><p class="MsoNormal"><strong><span style="font-size:100%;">So what’s the taphonomic connection?</span></strong></p> <p class="MsoNormal"><o:p> </o:p></p> <p class="MsoNormal">Well, none really. I considered weaving into a discussion on the taphonomic significance of broken bones, or the importance of pathologic features in the fossil record, but I didn’t want to distract from the main focus. A small mammal persevering in the harsh Eastern Montana climate with a deformed and vestigial hind limb is inspirational, if nothing else… <span style="mso-spacerun:yes"> </span></p><p class="MsoNormal"><br /></p><p class="MsoNormal"><span style="font-size:78%;">REFS</span></p><p class="MsoNormal"><span style="font-size:78%;">Wolniewicz, R. 2004. Field guide to skulls and bones of mammals of the northeastern United States, volume 2: the long bones. Richard Wolniewicz Publisher, Magnolia, MA, 97 p.</span></p>Benjamin Scherzerhttp://www.blogger.com/profile/06017783834589973483noreply@blogger.com1tag:blogger.com,1999:blog-9147223320739722188.post-74112340429894965192010-09-04T16:11:00.000-07:002010-09-04T17:46:17.252-07:00An Introduction to the Brule: Awareness of Sheepcamelpig<p class="MsoNormal"><span style="font-size:130%;">When we last left <st1:place st="on"><st1:placename st="on">Badlands</st1:placename> <st1:placetype st="on">National Park</st1:placetype></st1:place>, we had barely begun to scratch the surface, having covered only the Chadron Formation. While respectable in its own right, the Chadron is only a very small percentage of the park. The bulk of Badlands NP (literally) is formed by the Brule Formation – a complex, fossiliferous formation that has been awed for centuries.</span> </p> <a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEieC6-HBrqYIUHctH21c4u0QaQ7wfpEv3aUbjjBigx1Dh28wutZhT26KFkFXtE-TdRo26ey66RUM3Xy5xSiUHk-FM8s3MwqqCoJpZcUJhBS2sbKFBwWIwluPkUzQtIjVw5Ym8isOQYXiuo/s1600/20091123160121.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 268px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEieC6-HBrqYIUHctH21c4u0QaQ7wfpEv3aUbjjBigx1Dh28wutZhT26KFkFXtE-TdRo26ey66RUM3Xy5xSiUHk-FM8s3MwqqCoJpZcUJhBS2sbKFBwWIwluPkUzQtIjVw5Ym8isOQYXiuo/s400/20091123160121.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5513208265514894818" /></a> <p class="MsoNormal"><strong>Putting the “Land” in <st1:place st="on">Badlands</st1:place></strong></p> <p class="MsoNormal">As I mentioned previously, the Chadron Formation is the lowermost formation in the park, forming “haystack” buttes. The Brule, in contrast, is responsible for the archetypical badlands. The picture above, from the park’s own <a href="http://www.nps.gov/badl/photosmultimedia/Badlands-Scenery.htm">website</a> shows the cliff-forming Brule in all its glory, with prominent geographic features replete with funny names – castles, fingers, spires, hoodoos, and so on. (You can also see the color banding representative of the paleosols found throughout the formation, a topic worthy of its own blog post in the future…) The dramatic change between the landforms of the Chadron and Brule is very symbolic, as there was a significant change in paleoenvironment recorded in their respective depositional histories.</p> <p class="MsoNormal">The transition from the Chadron to the Brule represents the transition from the Eocene (55.8 – 33.9 Ma) to the Oligocene (33.9 – 23 Ma), a period of upheaval (again, literally) in <st1:place st="on">North America</st1:place> and also in the area of the future badlands. To the northwest, the uplift of the <st1:place st="on">Black Hills</st1:place> had peaked, and fluvial systems were carrying the eroded sediment through the area with a vengeance (Retallack, 1983). In addition, in the later stages of the Oligocene, enormous volcanic eruptions in <st1:state st="on">Nevada</st1:state> and <st1:state st="on">Utah</st1:state> were causing vast ashfall deposits on the plains immediately to the west, many of which were picked up and transported by wind into southwest <st1:state st="on"><st1:place st="on">South Dakota</st1:place></st1:state> (Larson and Evanoff, 1998). In addition, a gradual drying trend afflicted <st1:place st="on">North America</st1:place> during the Oligocene, turning the subtropical environments of the area into savannah-like grasslands. As a result, the Brule is actually subdivided into two members: the lower Scenic member, dominated by fluvially deposited mudstones representing a subhumid environment, and the upper Poleside member, dominated by eolian (wind-deposited) siltstones representing a semiarid environment, both of which are rich in volcaniclastics (Evanoff et al., 2010). The presence of the volcaniclastics makes the rocks of the Brule harder and more difficult to erode than those of the Chadron, allowing the creation of sharp, distinct badlands formations.</p> <p class="MsoNormal">Ecologically, the fauna were experiencing some upheaval (not literally, this time) of their own. The extinction of brontotheres at the end of the Eocene marked the beginning of the downfall of the once-dominant perissodactyls at the hands of diverse artiodactyls (Scott and Jepsen, 1940). Which is not to say that perissodactyls were reduced to the role of savannah wallflowers – “rhinos”* experienced their “culminating point” in North America at this time, and the beginning of the infamous evolution of horses began around the same time as well (Scott and Jepsen, 1940). But the ecosystems were clearly becoming dominated by artiodactyls, not the least of which are…</p> <p class="MsoNormal"><span style="font-size:85%;">*The quotation marks are intentional. For now, let’s not worry about exactly what that terms means…</span></p> <p class="MsoNormal"><strong>Oreodonts: dominant, diverse, damned confusing</strong></p> <a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKPTQ6aS-CeioMQFGXOEsaFp8boCF1YitQwz4bFEReGOitchg4pHUxindBfwr3TEnCb_01LDN3tzq2YQzXTFY7I_5Nr_GE-V5EafvPogcytzUkFnRJbG1xiTclFksDsql30ZqIPUAaUG0/s1600/oreodont.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 200px; height: 118px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKPTQ6aS-CeioMQFGXOEsaFp8boCF1YitQwz4bFEReGOitchg4pHUxindBfwr3TEnCb_01LDN3tzq2YQzXTFY7I_5Nr_GE-V5EafvPogcytzUkFnRJbG1xiTclFksDsql30ZqIPUAaUG0/s200/oreodont.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5513217864996498290" /></a> <p class="MsoNormal">Arguably the enigmatic taxa of the Badlands NP, and concurrently the Brule Formation, are the oreodonts (image at left from <a href="http://www3.uni-bonn.de/die-universitaet/informationsquellen/presseinformationen/pressemitteilungen/282_02?set_language=fr">here</a>), a diverse group of controversial affinity. Two taxa, the small, bizarre <i style="mso-bidi-font-style:normal">Leptauchenia</i>, and larger <i style="mso-bidi-font-style:normal">Merycoidodon,</i> are the most common forms in the park. They have no modern representatives, so are commonly described as “pig-like” or “sheep-like.” As it turns out, they share some features with possible camel ancestors, so “camel-sheep-pig” may actually be more fitting, though no more helpful. They are allegedly the most common large mammals in the Brule Formation “by far,” with <i style="mso-bidi-font-style:normal">Merycoidodon</i> distinguished as “the most common of all badlands fossils” (Prothero and Whittlesey, 1998). In fact, Hayden (1857) originally referred to the Scenic member the “Turtle and Oreodon* beds,” and the Poleside member as the “Leptauchenia beds**.” Furthermore, oreodont fossils are abundant and obvious enough in Badlands NP that they are the most commonly reported fossils by visitors, and not by a small margin (personal observation).</p> <p class="MsoNormal"><span style="font-size:85%;">* Again, not a typo. We’ll get to that in a few minutes…</span></p><span style="font-size:85%;"> </span><p class="MsoNormal"><span style="font-size:85%;">** For the record, naming formations or members by common fossils was not an atypical practice by early geologists at all. This is a thoroughly bad idea for a number of reasons, but unfortunately they didn’t let that stop them, so now we have to deal with the results.</span></p> <a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEik-z-LBkaL_3iQcL1dLrYZ7WbdmaVbr051vcJXHNjfg_-UQjc-PFDy2T-lVVsz5xEn8sZv3f0rYnqW2ej7-t3Wvwy7mF8OPSxVh3hkFufy7CCIDZt2lC10Xftmsb7QKBPduQemtEcw3VA/s1600/lepta.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 162px; height: 320px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEik-z-LBkaL_3iQcL1dLrYZ7WbdmaVbr051vcJXHNjfg_-UQjc-PFDy2T-lVVsz5xEn8sZv3f0rYnqW2ej7-t3Wvwy7mF8OPSxVh3hkFufy7CCIDZt2lC10Xftmsb7QKBPduQemtEcw3VA/s320/lepta.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5513218821500098514" /></a> <p class="MsoNormal">They are also a very diverse group, with an incredible variety in body forms. The aforementioned <i style="mso-bidi-font-style:normal">Leptauchenia</i>, for example, has a markedly unusual skull that caused many earlier researchers to assume it led a lifestyle similar to modern beavers (see Scott and Jepsen, 1940, the source of the images at left). Unfortunately, this diversity has led to a lot of oversplitting (inappropriate naming of new taxa), with a lot of confusing terminology – for example, the name “Oreodon” is the above paragraph is actually an older name for <i style="mso-bidi-font-style:normal">Merycoidodon</i>, an oreodont, and a large number of oreodonts are now classified under the group <em>Merycoidodontidae</em> (still with me?). Robert Carroll’s exhaustive “Vertebrate Paleontology and Evolution” (1988), in fact, doesn’t even list the term “oreodont,” as it is apparently not a valid name for the group. Not surprisingly, the group as a whole is currently undergoing a lot of professional revision (Benton, Miller, Weiler, etc, personal communication, 2010). Regardless, oreodonts are still a fascinating group, and there is much more to say about them, but I will leave that for a future post…</p><p class="MsoNormal"><br /></p><p class="MsoNormal"><br /></p><p class="MsoNormal"><br /></p><p class="MsoNormal" align="center"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://rusalka.artspots.com/"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 200px; height: 200px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgggkfevvLXhWZuFvyqm1L3EUWZCedVvnF4tj6LejSWid6V7bN4v3B5sUupk8jY_41hqR6ry2ZKsY1opt7sV6X7UjJ2-EdqqJ2ZuYybZcMtgDXu0m_H1wWtE4CB3bw_TNlM_bnHtKa8IPo/s200/mylittleoreoweb_thumb_400.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5513219297256445954" /></a><span style="font-size:85%;">No, you didn't really see this. Keep scrolling.</span></p><p class="MsoNormal"><span style="font-size:85%;"><br /></span></p><p class="MsoNormal"> <p class="MsoNormal"><span style="font-size:78%;">REFS</span></p><p class="MsoNormal"><span style="font-size:78%;">Carroll, R.L. 1988. Vertebrate Paleontology and Evolution. WH Freeman and Company, </span><st1:state st="on"><st1:place st="on"><span style="font-size:78%;">New York</span></st1:place></st1:state><span style="font-size:78%;">, 698 p.</span></p><p class="MsoNormal"><span style="font-size:78%;">Evanoff, E.E., Terry, D.O., Jr., </span><st1:place st="on"><st1:city st="on"><span style="font-size:78%;">Benton</span></st1:city></st1:place><span style="font-size:78%;">, R.C., and Minkler, H. 2010. Field guide to the geology of the White River Group in the North Unit of Badlands National Park: a guide for the field trip: recent advances in understanding the geologic history of the White River Badlands, 24-25 April 2010: GSA Rocky Mountain Section Meeting, 21-23 April 2010, Rapid City, SD, USA.</span></p><span style="font-size:78%;"> </span><p class="MsoNormal"><span style="font-size:78%;">Hayden, F.V. 1857. Notes on the geology of the Mauvaises Terres of </span><st1:place st="on"><st1:city st="on"><span style="font-size:78%;">White River</span></st1:city><span style="font-size:78%;">, </span><st1:state st="on"><span style="font-size:78%;">Nebraska</span></st1:state></st1:place><span style="font-size:78%;">: Proceedings of the Academy of Natural Sciences of Philadelphia, v. 9, p. 151-158.</span></p><span style="font-size:78%;"> </span><p class="MsoNormal"><span style="font-size:78%;">Larson, E.E., and Evanoff, E. 1998. Tephrostratigraphy and sources of the tuffs of the </span><st1:place st="on"><span style="font-size:78%;">White River</span></st1:place><span style="font-size:78%;"> sequence, </span><i style="mso-bidi-font-style:normal"><span style="font-size:78%;">in</span></i><span style="font-size:78%;"> Terry, D.O., Jr., LaGarry, H.E., and Hunt, R.M., eds., Depositional environments, lithostratigraphy, and biostratigraphy of the White River and Arikaree Groups (Late Eocene to Early Miocene, North America): Geological Society of America Special Paper 325, p. 1-14).</span></p><span style="font-size:78%;"> </span><p class="MsoNormal"><span style="font-size:78%;">Prothero, D. R., and Whittlesey, K.E. 1998. Magnetic stratigraphy and biostratigraphy of the Orellan and Whitneyan land mammal "ages" in the White River Group, </span><i style="mso-bidi-font-style:normal"><span style="font-size:78%;">in</span></i><span style="font-size:78%;"> Terry, D.O., Jr., LaGarry, H.E., and Hunt, R.M., Jr., eds, Depositional Environments, Lithostratigraphy, and Biostratigraphy of the White River and Arikaree Groups (Late Eocene to Early Miocene, North America): Geological Society of America, Special Paper 325, p. 39-61.</span></p><span style="font-size:78%;"> </span><p class="MsoNormal"><span style="font-size:78%;">Retallack, G.J. 1983. Late Eocene and Oligocene paleosols from </span><st1:place st="on"><st1:city st="on"><span style="font-size:78%;">Badlands National Park</span></st1:city><span style="font-size:78%;">, </span><st1:state st="on"><span style="font-size:78%;">South Dakota</span></st1:state></st1:place><span style="font-size:78%;">: Geological Society of America Special Paper 193, 82 p.</span></p><span style="font-size:78%;"> </span><p class="MsoNormal"><span style="font-size:78%;">Scott, W.B., and Jepsen, G.L. 1940. The mammalian fauna of the White River Oligocene: Part IV, Artiodactyla: Transactions of the American Philosophical Society, New Series, v. 28, no.4, p. 363-746.</span></p> <span style="font-size:85%;"><br /></span>Benjamin Scherzerhttp://www.blogger.com/profile/06017783834589973483noreply@blogger.com2tag:blogger.com,1999:blog-9147223320739722188.post-18190630615616795762010-08-01T15:22:00.000-07:002010-08-01T17:19:47.599-07:00Why Looking for a Hidden River is like Searching for the Right Asylum<p class="MsoNormal"><span style="font-size:130%;">Back in my college days, I was lucky enough to intern at the Cleveland Museum of Natural History for one summer. One aspect of my project involved studying the quarrying history of a local building stone. In the course of my research, I noticed that on many 1800s-era geologic maps, asylums were often located very near to quarries. As it turns out, this was not a coincidence – quarries often hired asylums resident as cheap labor, and in turn, the residents got a chance to leave the grounds and get some stimulation. Hence, a somewhat disturbing lesson: if older geologic maps don’t show quarries, look for asylums. Investigating the geologic record often works in the same vein.</span></p> <p class="MsoNormal"><span style="font-size:100%;">As it turns out, the majority of geologic events in the earth’s history were never preserved in the rock record. Even a geologic event that is sufficiently significant, long-lived, and plainly lucky enough to be preserved may never be discovered – it has to be exposed, accessible, and properly observed and studied. Often, geologic events are not interpreted based on their direct effects, but by side effects and related events. Metaphorically speaking, the quarries are gone, but the asylums remain. In a prime example, in looking for evidence of an ancient transcontinental river in the </span><st1:country-region st="on"><st1:place st="on"><span style="font-size:100%;">U.S.</span></st1:place></st1:country-region><span style="font-size:100%;">, geologists had to look in….desert deposits. </span></p><span style="font-size:100%;"> </span><p class="MsoNormal"><strong><span style="font-size:100%;">How to find evidence of a river nobody can see</span></strong></p><span style="font-size:100%;"> </span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8QTw68_9bDR3eqfKHOREHDaLOEherbkAADMeAqBtKS2fWTaqpUabEaKdVwUt1sL6r8YgE_otTqLTM_riTlma18ZVCGT2zdKfIsBmoLaq5ZYJ1vtO49md1Y-SPlTeiftumbPY4AeoQtJA/s1600/Image1.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 200px; height: 133px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8QTw68_9bDR3eqfKHOREHDaLOEherbkAADMeAqBtKS2fWTaqpUabEaKdVwUt1sL6r8YgE_otTqLTM_riTlma18ZVCGT2zdKfIsBmoLaq5ZYJ1vtO49md1Y-SPlTeiftumbPY4AeoQtJA/s200/Image1.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5500571221925281090" /></a><span style="font-size:100%;"> </span><p class="MsoNormal"><span style="font-size:100%;">Many of the archetypical rock formations of the American southwest – the towering red cliffs, psychedelically wavy hillsides, etc (pictures at left from <a href="http://venturacountytrails.org/News/0182-TheWaveVermilionCliffs/NewsPage.htm">here</a>) – are the deposits of ancient Jurassic ergs* (sand seas). These ergs were particularly enormous – perhaps rivaling in size the </span><a href="http://ngm.nationalgeographic.com/ngm/0502/sights_n_sounds/media2.html"><span style="font-size:100%;">Empty Quarter</span></a><span style="font-size:100%;"> in the </span><st1:place st="on"><span style="font-size:100%;">Arabian Peninsula</span></st1:place><span style="font-size:100%;"> (the largest modern erg) (Dickinson and Gehrels, 2009). </span></p><span style="font-size:100%;"> </span><p class="MsoNormal"><span style="font-size:100%;">With any erg, the obvious question is “where did all the sand come from”? (Granitic crust is only 1/3</span><sup><span style="font-size:100%;">rd</span></sup><span style="font-size:100%;"> quartz at most, so a lot of rock has to be eroded to get a sand sea). Two easy answers presented themselves – the (Ancestral**) Rocky Mountains are practically next door, and there were plenty of voluminous sandstones across </span><st1:place st="on"><span style="font-size:100%;">North America</span></st1:place><span style="font-size:100%;"> that could have been reworked. But there was also a third possibility, first proposed by Marzolf (1988) – an enormous transcontinental river originating in the </span><st1:place st="on"><span style="font-size:100%;">Appalachians</span></st1:place><span style="font-size:100%;"> on the east coast. Unfortunately, Jurassic rocks aren’t exposed anywhere in the </span><st1:country-region st="on"><span style="font-size:100%;">U.S.</span></st1:country-region><span style="font-size:100%;"> between the Rockies and the </span><st1:place st="on"><span style="font-size:100%;">Appalachians</span></st1:place><span style="font-size:100%;">, so direct evidence of this river was out of the question. But, there are the ergs…</span></p><p class="MsoNormal" align="center"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7ggoUBi7gEu4jtYpDdtYzFWE5ak0gPcooIA5xIjT3uwQz-k9nnOe0-U-xueAuf7XX3CEcJTnprb2UEtQelOoyxsREIBznIblXRKxh4T8ZRbPla7KRRNMIxf1lPYRMrAfgUsf-b8G5Y3g/s1600/1834562-The_Empty_Quarter-Saudi_Arabia.jpg"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 200px; height: 134px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7ggoUBi7gEu4jtYpDdtYzFWE5ak0gPcooIA5xIjT3uwQz-k9nnOe0-U-xueAuf7XX3CEcJTnprb2UEtQelOoyxsREIBznIblXRKxh4T8ZRbPla7KRRNMIxf1lPYRMrAfgUsf-b8G5Y3g/s200/1834562-The_Empty_Quarter-Saudi_Arabia.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5500572360269675682" /></a><span style="font-size:85%;"><st1:place st="on"><st1:city st="on">Aspen</st1:city>, <st1:state st="on">Colorado</st1:state></st1:place>, circa 170,000,000 years ago (from <a href="http://members.virtualtourist.com/m/7d287/bc1/">here</a>)</span></p><span style="font-size:78%;"> </span><p class="MsoNormal"><span style="font-size:78%;">* Deserts and ergs aren’t synonymous, but the two coincided in this instance.</span></p><span style="font-size:78%;"> </span><p class="MsoNormal"><span style="font-size:78%;">** Not the same as the modern </span><st1:place st="on"><span style="font-size:78%;">Rocky Mountains</span></st1:place><span style="font-size:78%;">, but let’s not get into that right now…</span></p> <p class="MsoNormal"><span style="font-size:100%;">Marzolf’s hypothesis was essentially ignored until </span><st1:place st="on"><st1:placetype st="on"><span style="font-size:100%;">University</span></st1:placetype><span style="font-size:100%;"> of </span><st1:placename st="on"><span style="font-size:100%;">Arizona</span></st1:placename></st1:place><span style="font-size:100%;"> geologists William Dickinson (emeritus) and George </span><a href="http://www.geo.arizona.edu/web/Gehrels/GG_page.html"><span style="font-size:100%;">Gehrels</span></a><span style="font-size:100%;"> decided to take a look at some of the deposits in the Jurassic ergs in the 1990s. Specifically, they looked at the zircons in the sandstones – unlike the commercials, zircons, not diamonds, are forever in the geologic record, lasting hundreds of millions of years (the oldest known mineral on earth is actually a zircon (Wilde et al., 2001)). Over their long lifespan, zircons can be transported and reworked over thousands of kilometers, but always carry an age signature from their original host rock. When sandstone were sampled from various localities in the ergs, the ages of the zircons fell into three categories: 1/4</span><sup><span style="font-size:100%;">th</span></sup><span style="font-size:100%;"> matched ages with the basement rocks of the Ancestral Rockies, 1/4</span><sup><span style="font-size:100%;">th</span></sup><span style="font-size:100%;"> matched ages with reworked ancient sandstones, and the remaining half were divided into four ages too young for the previous two categories (Dickinson and Gehrels, 2003). When the younger zircons were investigated further, it was discovered that the four age ranges fit nicely with….granite bodies that compose the </span><st1:place st="on"><span style="font-size:100%;">Appalachians</span></st1:place><span style="font-size:100%;"> (Dickinson and Gehrels, 2009). Furthermore, paleowind measurements from the sandstones showed consistent southern winds (Dickinson and Gehrels, 2009). Combined, this suggested there was some major source of transportation that carried sands from the Appalachians to the western </span><st1:place st="on"><st1:country-region st="on"><span style="font-size:100%;">U.S.</span></st1:country-region></st1:place><span style="font-size:100%;">, where they were deposited and carried by winds to build ergs to the south (see cartoon below, heavily inspired by Fig. 1 in Dickinson et al., 2010). And a prime candidate would be….a major transcontinental river!</span></p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjonWPshDc4NHFOLLl_vULOus0jRTIEmLEATRZTrsPrf1i-VlwD7Fa3AXtuHgniNauGwVvHHXuYIuaQ1_EDygxYyCaJNwT8owBVdLzJ77fwa4nU3ZVBK9e30VeCBCABT6q9GyQKsPnK5kw/s1600/temp.jpg"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 250px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjonWPshDc4NHFOLLl_vULOus0jRTIEmLEATRZTrsPrf1i-VlwD7Fa3AXtuHgniNauGwVvHHXuYIuaQ1_EDygxYyCaJNwT8owBVdLzJ77fwa4nU3ZVBK9e30VeCBCABT6q9GyQKsPnK5kw/s400/temp.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5500573065197945746" /></a><span style="font-size:100%;"> </span><p class="MsoNormal"><strong><span style="font-size:100%;">The long history of Canadian immigration</span></strong></p><span style="font-size:100%;"> </span><p class="MsoNormal"><span style="font-size:100%;">Recently, Dickinson et al. (2010) tested the "transcontinental river" hypothesis from another angle. I mentioned before that Jurassic rocks aren’t exposed between the Rockies and the </span><st1:place st="on"><span style="font-size:100%;">Appalachians</span></st1:place><span style="font-size:100%;">, but they do exist – under a whole bunch of other rocks. In this case, Dickinson et al. (2010) compared sandstones from the Jurassic ergs to the west to subsurface (fluvial) Jurassic sandstones in the Michigan Basin (star in figure above), an area that would have been right in the middle of some of the northern tributaries of the transcontinental river. This time, the zircon ages were more nuanced: the ergs and the fluvial sandstones both contained zircons with ages matching “Grenvillian” source rocks, but the zircons from the </span><st1:state st="on"><st1:place st="on"><span style="font-size:100%;">Michigan</span></st1:place></st1:state><span style="font-size:100%;"> sandstones lacked ages matching “peri-Gondwanan” source rocks (Dickinson et al., 2010). As it turns out, the “Grenvillian” source rocks are found in northeast </span><st1:country-region st="on"><span style="font-size:100%;">Canada</span></st1:country-region><span style="font-size:100%;">, and the “peri-Gondwanan” rocks are found in the southern </span><st1:place st="on"><span style="font-size:100%;">Appalachians</span></st1:place><span style="font-size:100%;">. So it would make sense that tributaries from northeast Canada (upper arrow in figure above) would carry zircons that ended up in </span><st1:state st="on"><span style="font-size:100%;">Michigan</span></st1:state><span style="font-size:100%;"> and eventually the western ergs, but tributaries from the southeast </span><st1:country-region st="on"><st1:place st="on"><span style="font-size:100%;">U.S.</span></st1:place></st1:country-region><span style="font-size:100%;"> (lower arrow in figure above) would carry zircons that ended up in the western ergs only (Dickinson et al., 2010).</span> </p> <p class="MsoNormal"><o:p> </o:p></p> <p class="MsoNormal"><span style="font-size:78%;">REFS</span></p><span style="font-size:78%;"> </span><p class="MsoNormal"><st1:city st="on"><st1:place st="on"><span style="font-size:78%;">Dickinson</span></st1:place></st1:city><span style="font-size:78%;">, W.R., and Gehrels, G.E. 2003. U-Pb ages of detrital zircons from Permian and Jurassic eolian sandstones of the Colorado Plateau, USA: Paleogeographic implications: Sedimentary Geology, v. 163, p. 29–66. (pdf <a href="http://www.ees.lehigh.edu/ftp/retreat/outgoing/for_team_appalachians/appalachians_paper/dickinson_gerhrels_2003_sedimentary_geology_zircons.pdf">here</a>)</span></p><span style="font-size:78%;"> </span><p class="MsoNormal"><st1:city st="on"><st1:place st="on"><span style="font-size:78%;">Dickinson</span></st1:place></st1:city><span style="font-size:78%;">, W.R., and Gehrels, G.E., 2009. U-Pb ages of detrital zircons in Jurassic eolian and associated sandstone of the Colorado Plateau: Evidence for transcontinental dispersal and intraregional recycling of sediment: Geological Society of America Bulletin, v. 121, p. 408–433. </span></p><span style="font-size:78%;"> </span><p class="MsoNormal"><st1:city st="on"><st1:place st="on"><span style="font-size:78%;">Dickinson</span></st1:place></st1:city><span style="font-size:78%;">, W.R., Gehrels, G.E., and Marzolf, J.E. 2010. Detrital zircons from fluvial Jurassic strata of the </span><st1:place st="on"><st1:state st="on"><span style="font-size:78%;">Michigan</span></st1:state></st1:place><span style="font-size:78%;"> basin: Implications for the transcontinental Jurassic paleoriver hypothesis: Geology, v. 38, no. 6, p. 499–502. </span></p><span style="font-size:78%;"> </span><p class="MsoNormal"><span style="font-size:78%;">Marzolf, J.E., 1988. Controls on late Paleozoic and early Mesozoic eolian deposition of the western </span><st1:place st="on"><st1:country-region st="on"><span style="font-size:78%;">United States</span></st1:country-region></st1:place><span style="font-size:78%;">: Sedimentary Geology, v. 56, p. 167–191.</span> </p><p class="MsoNormal"><span style="font-size:78%;">Wilde, S.A., Valley, J.W., Peck, W.H., and Graham C.M. 2001. Evidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr ago: Nature, v. 409, p. 175-178. (pdf <a href="http://www.falw.vu/~wijj/MSc%20courses/Cursus%20Precambrium%20Geologie%202003/literature%20Istopes/WildeNature'01.pdf">here</a>)<br /></span></p>Benjamin Scherzerhttp://www.blogger.com/profile/06017783834589973483noreply@blogger.com0tag:blogger.com,1999:blog-9147223320739722188.post-30822209782092802822010-06-16T17:05:00.000-07:002010-08-01T15:53:10.508-07:00An Afternoon Spent Packing Heat, or, An Introduction to the Chadron<p><span style="font-size:130%;">The focus on <st1:place st="on"><st1:placename st="on">Badlands</st1:placename> <st1:placetype st="on">National Park</st1:placetype></st1:place> persists, with a post inspired by a recent field outing. In this case, the objective was potentially radioactive sedimentary rocks, but a brief introduction to one of the formations of Badlands NP is warranted:</span></p><p><span style="font-size:130%;"><strong>Act I: A troubled upbringing</strong><br /></span></p><p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8HSl8Xfn3Fj8CYhaWQhfHFyJhkMRKTr9RAlPzG-lQ7c3bCbCj5HPtFEWzVIj1p-cZxOAt7IlKzWvDcywD8u63ljkjDK98ajNHhsEy9_9oMfyZr3boLLO-83wmP83DL12ftFls3yi_8Yc/s1600/44796-050-45777DF0.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 200px; height: 168px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8HSl8Xfn3Fj8CYhaWQhfHFyJhkMRKTr9RAlPzG-lQ7c3bCbCj5HPtFEWzVIj1p-cZxOAt7IlKzWvDcywD8u63ljkjDK98ajNHhsEy9_9oMfyZr3boLLO-83wmP83DL12ftFls3yi_8Yc/s200/44796-050-45777DF0.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5483528716130270834" /></a></p><p class="MsoNormal">The Chadron Formation (32 – 37 Ma) has a troubled history, not unlike many formations in the western <st1:place st="on"><st1:country-region st="on">United States</st1:country-region></st1:place>. It was originally (and still commonly) distinguished by its “<i style="mso-bidi-font-style:normal">Titanotherium</i> beds/graveyards” (e.g. Hayden, 1857; Clark, 1937), referring to the remains of the huge (Asian elephant-sized) animals now called brontotheres (reconstruction seen at right from <a href="http://www.britannica.com/EBchecked/topic-art/320328/95178/A-reconstruction-of-fossil-Perissodactyla-showing-Brontops-a-titanothere-from">here</a>). This is a problematic term, as brontotheres are actually rare in the formation (Prothero and Whittlesey, 1998), and the famous “graveyards” may not actually be plural (see Harksen and Macdonald, 1969). Regardless, brontotheres are very large and distinct fossils, and are restricted to the Chadron in the area of Badlands NP, as far as I know. A type section for the Chadron was eventually assigned (Harksen and Macdonald, 1969), but is admittedly of poor quality, and the boundary with the overlying Brule is “basically continuous” (Stoffer, 2003), causing some individuals (including myself) to wonder why they are considered separate formations…</p> <a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikIFlbNZL-9IwhVLDhVOYvSvIXJJu3V8qAfCNQlrCYFTx1bnLOp7JTY0I7oBLpr35ZuIrMAjIAN0ebNVKhmzqDtaJ63TPjmajQVmXGWRRtrFoTovgWfOdgXZNeFrbvTdMUE455jBdlYJI/s1600/Untitled-1.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 200px; height: 112px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikIFlbNZL-9IwhVLDhVOYvSvIXJJu3V8qAfCNQlrCYFTx1bnLOp7JTY0I7oBLpr35ZuIrMAjIAN0ebNVKhmzqDtaJ63TPjmajQVmXGWRRtrFoTovgWfOdgXZNeFrbvTdMUE455jBdlYJI/s200/Untitled-1.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5483531660650698930" /></a><p class="MsoNormal">Anyways, the Chadron Formation is one of the lowermost beds in the stratigraphy of <st1:place st="on"><st1:placename st="on">Badlands</st1:placename> <st1:placetype st="on">National Park</st1:placetype></st1:place>, directly underlying the cliff-forming Brule Formation. It is predominantly green to grey massive mudrocks and (particularly towards the top) thin marls and limestones. It is also relatively shy in the north unit of the park, but is (allegedly) beautifully exposed in the south unit*. Assigning rocks to the Chadron is a rather casual affair in the park, as most poorly consolidated mudrocks of Late Eocene age are uncritically tossed into the formation (Stoffer, 2003). The high clay content in the Chadron causes them to weather into rolling “haystack” buttes, in contrast to the sharp cliff-like buttes of the Brule (image at left from Stoffer, 2003). The Chadron exhibits the last of the environment that existed in the Eocene in the Badlands NP area, documenting extensive streamside forests, low sedimentation rates, and strongly developed paleosols (Retallack, 1983). Also, in contrast to later beds, mammal fossils are most common in channels sands, not paleosols (Retallack, 1983).</p> <p class="MsoNormal"><span style="font-size:78%;">* I have not yet explained – Badlands NP has a north unit and a south unit, with a thin strip connecting the two; the park is shaped like a big, sheared dumbbell. And there’s also a chunk of park to the east of the south unit. </span></p> <p class="MsoNormal"><strong>Act II: I defy the basic physics of radiation</strong></p><p class="MsoNormal">Anyways, in the upper Chadron Formation just outside the park boundary in the south unit is an exposure of channel sandstones with uranium-rich minerals at its base. It is suspected that downward-moving meteoric water carried uranium from overlying ash beds until it reached the base of the sandstone, which is underlain by an impenetrable claystone (Moore and Levish, 1955). I made it my duty last Sunday to try and find this exact sandstone. Thankfully, the original publication on the sandstone (Moore and Levish, 1955), includes a marked topographic map and photographs, so I was in luck. After roughly two hours of hiking over distinctly different terrain depending on which side of the tables I was on, I came upon the following exposure (photo from <st1:city st="on"><st1:place st="on">Moore</st1:place></st1:city> and Levish (1955) on left, with the same ridge marked "A" in both images for comparison):</p> <a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWAgxczOM0E50-s8oZhF6TZadjue5SPffAC2lzIiKOiCod2UVRdU_waUkQuTg3qNymtrMQ7MCtLRFyCgC8adXdZw6YZ3u9sdD_q3qk_lVCvBLF_8rBuEpbp4Znd0uU8B4y1EFoNCFAB8Q/s1600/6-15-2010+8.jpeg"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 115px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjWAgxczOM0E50-s8oZhF6TZadjue5SPffAC2lzIiKOiCod2UVRdU_waUkQuTg3qNymtrMQ7MCtLRFyCgC8adXdZw6YZ3u9sdD_q3qk_lVCvBLF_8rBuEpbp4Znd0uU8B4y1EFoNCFAB8Q/s400/6-15-2010+8.jpeg" border="0" alt="" id="BLOGGER_PHOTO_ID_5483533823877834370" /></a> <p class="MsoNormal">As I approached the area marked by the arrow of <st1:city st="on"><st1:place st="on">Moore</st1:place></st1:city> and Levish (1955) (it's in the middle, and very small), the infamous sandstone was exposed in all its glory (backpack at lower right for scale):</p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAZ0A6TRwFc85AstTIA6qvHHZsIsMQgE-yDC0oB2ozd4BMyd9BmskbmItVeCCbOHnDUPS6PhjxuAitvQMfqmah_uuFNYfm-iWSeaCMdh7MAHQ7547dB2ERwnThGRrJDiE0MCCC5rqeDwA/s1600/IMG_8536.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiAZ0A6TRwFc85AstTIA6qvHHZsIsMQgE-yDC0oB2ozd4BMyd9BmskbmItVeCCbOHnDUPS6PhjxuAitvQMfqmah_uuFNYfm-iWSeaCMdh7MAHQ7547dB2ERwnThGRrJDiE0MCCC5rqeDwA/s400/IMG_8536.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5483534842553786322" /></a><p class="MsoNormal">I collected a few samples from the base of the (very well cemented) sandstone, but I won’t know if I was truly successful until I find a Geiger Counter or a bored petrologist. Interestingly, some bone fragments were also found nearby, with distinct coloration. Here, for instance is a cross-section of a distal ungulate tibia (cyan book cover background for color enhancement):</p> <a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9c2ZuInIZ9QxHzUS1YsEX7C3NRuxY_x5P_jpBpv5etNQAnV4wQ_iSUFmwYbFy1bQMYkOskO5LhXsvZkZ_88UALEjUVoQlyff36iZtF7Omw1py6pVuwAlAN556R1bQTQ2GCY1-jGGaXc4/s1600/IMG_8546.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9c2ZuInIZ9QxHzUS1YsEX7C3NRuxY_x5P_jpBpv5etNQAnV4wQ_iSUFmwYbFy1bQMYkOskO5LhXsvZkZ_88UALEjUVoQlyff36iZtF7Omw1py6pVuwAlAN556R1bQTQ2GCY1-jGGaXc4/s400/IMG_8546.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5483535280959225746" /></a> <p class="MsoNormal">The yellow "rim" is notable - bright oranges and yellows are not uncommon for fossils from the area of Badlands NP, and are suspected to indicate the fossils might be radioactive (M. Cherry, personal communication). Considering the nature of the nearby uranium-bearing sandstones, this is not particularly surprising. As I mentioned before, fossils are most common in channel sandstones in the Chadron (Retallack, 1983), and bones commonly show high concentrations of certain minerals relative to the surrounding rocks, due to their difference in porosity. However, while radioactive fossils are not uncommon (e.g. Farmer et al., 2008), I have not been able to find literature that details why these brightly-colored fossils in Badlands NP are specifically suspected to potentially be radioactive. For now, I am left unsure if this assumption is based on mineralogical studies (good) or just color comparison (bad).</p><p class="MsoNormal"><o:p> </o:p></p> <p class="MsoNormal"><span style="font-size:85%;">REFS </span></p><span style="font-size:85%;"> </span><p class="MsoNormal"><span style="font-size:85%;">Clark, J. 1937. The stratigraphy and paleontology of the Chadron Formation in the Big Badlands of South Dakota: Carnegie Museum Annals, v. 25, p. 261-350. </span></p><span style="font-size:85%;"> </span><p class="MsoNormal"><span style="font-size:85%;">Farmer C.N., Kathren, R.L., and Christensen, C. 2008. Radioactivity in fossils at the </span><st1:place st="on"><st1:placename st="on"><span style="font-size:85%;">Hagerman</span></st1:placename><span style="font-size:85%;"> </span><st1:placename st="on"><span style="font-size:85%;">Fossil</span></st1:placename><span style="font-size:85%;"> </span><st1:placename st="on"><span style="font-size:85%;">Beds</span></st1:placename><span style="font-size:85%;"> </span><st1:placetype st="on"><span style="font-size:85%;">National Monument</span></st1:placetype></st1:place><span style="font-size:85%;">: Journal of Environmental Radioactivity, vol. 99, no. 8, p. 1355-1359. </span></p><p class="MsoNormal"><span style="font-size:85%;">Harksen, J.C., and Macdonald, J.R. 1969. Type sections for the Chadron and Brule Formations of the White River Oligocene in the Big Badlands of South Dakota: South Dakota Geological Survey Report of Investigations 99, 23 p.</span></p><p class="MsoNormal"><span style="font-size:85%;">Hayden, F.V. 1857. Notes on the geology of the Mauvaises Terres of </span><st1:place st="on"><st1:city st="on"><span style="font-size:85%;">White River</span></st1:city><span style="font-size:85%;">, </span><st1:state st="on"><span style="font-size:85%;">Nebraska</span></st1:state></st1:place><span style="font-size:85%;">: Proceedings of the Academy of Natural Sciences of Philadelphia, v. 9, p. 151-158.</span></p><p class="MsoNormal"><st1:place st="on"><st1:city st="on"><span style="font-size:85%;">Moore</span></st1:city></st1:place><span style="font-size:85%;">, G.W., and Levish, M. 1955. Uranium-bearing sandstone in the White River Badlands, </span><st1:place st="on"><st1:city st="on"><span style="font-size:85%;">Pennington County</span></st1:city><span style="font-size:85%;">, </span><st1:state st="on"><span style="font-size:85%;">South Dakota</span></st1:state></st1:place><span style="font-size:85%;">: </span><span style="font-size:85%;">U.S. Geological Survey Circular 359, 7 p.</span></p><p class="MsoNormal"><span style="font-size:85%;">Prothero, D. R., and Whittlesey, K.E. 1998. Magnetic stratigraphy and biostratigraphy of the Orellan and Whitneyan land mammal "ages" in the White River Group, </span><i style="mso-bidi-font-style:normal"><span style="font-size:85%;">in</span></i><span style="font-size:85%;"> Terry, D.O., Jr., LaGarry, H.E., and Hunt, R.M., Jr., eds, Depositional Environments, Lithostratigraphy, and Biostratigraphy of the White River and Arikaree Groups (Late Eocene to Early Miocene, North America): Geological Society of America, Special Paper 325, p. 39-61.</span></p><span style="font-size:85%;"> </span><p class="MsoNormal"><span style="font-size:85%;">Retallack, G.J. 1983. Late Eocene and Oligocene paleosols from </span><st1:place st="on"><st1:city st="on"><span style="font-size:85%;">Badlands National Park</span></st1:city><span style="font-size:85%;">, </span><st1:state st="on"><span style="font-size:85%;">South Dakota</span></st1:state></st1:place><span style="font-size:85%;">: Geological Society of America Special Paper 193, 82 p.</span></p><p class="MsoNormal"><span style="font-size:85%;">Stoffer, P.W. 2003. Geology of </span><st1:placename st="on"><span style="font-size:85%;">Badlands</span></st1:placename><span style="font-size:85%;"> </span><st1:placetype st="on"><span style="font-size:85%;">National Park</span></st1:placetype><span style="font-size:85%;">: A Preliminary Report: </span><st1:country-region st="on"><st1:place st="on"><span style="font-size:85%;">U.S.</span></st1:place></st1:country-region><span style="font-size:85%;"> Geological Survey, Open-File Report 03-35, 62 p. (pdf available </span><a href="http://geopubs.wr.usgs.gov/open-file/of03-35/of03-35.pdf"><span style="font-size:85%;">here</span></a><span style="font-size:85%;">)</span></p> <p class="MsoNormal"><o:p> </o:p></p>Benjamin Scherzerhttp://www.blogger.com/profile/06017783834589973483noreply@blogger.com1tag:blogger.com,1999:blog-9147223320739722188.post-80195381253312447782010-06-01T19:59:00.001-07:002010-08-01T15:52:43.204-07:00Badlands Background, part I: Soils Past and Present<p class="MsoNormal"><span style="font-size:130%;">After a not-insignificant hiatus, blog entries have resumed. For the record, I would personally not recommend starting up a blog before: (1) traveling overseas, (2) getting violently ill, (3) returning home to hurriedly prepare to move to another state, (4) starting a new job, and (5) trying to finalize a manuscript for publication, in that or any order. Regardless, I have recently assumed a seasonal position at <st1:place st="on"><st1:city st="on">Badlands National Park</st1:city>, <st1:state st="on">South Dakota</st1:state></st1:place>. Due to the literal backyard accessibility and extensive library collections, many of the posts in the near future will likely be focused on Badlands NP geology and paleontology. So, I figured it would be prudent to give a brief background.</span></p> <p class="MsoNormal"><span style="font-size:85%;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDxIGo23w6O2X5IdsOHbXYTX9oSytXZZ2YFdX7V4czeNzeqf9vyOzc04XTIx9aeSijUP1x8wPzry4XmzUPYXCfskjAqAxY7RxXRgeIl3ICw83dyUcx0bae8JUi2COCITuMzjwzdlQ6vIE/s1600/BruceSpringsteenDarknessontheEdgeofTown.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 200px; height: 196px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDxIGo23w6O2X5IdsOHbXYTX9oSytXZZ2YFdX7V4czeNzeqf9vyOzc04XTIx9aeSijUP1x8wPzry4XmzUPYXCfskjAqAxY7RxXRgeIl3ICw83dyUcx0bae8JUi2COCITuMzjwzdlQ6vIE/s200/BruceSpringsteenDarknessontheEdgeofTown.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5478006468407022578" /></a></span><span style="font-size:100%;">The first question, even among practicing geologists, may be “What exactly are badlands?” Unfortunately, “badlands” has come to be defined by consensus rather than by strict criteria, referring to terrain dominated by steep, rugged hills of loose sediment with little to no vegetation. Their creation results from a combination of loose, sandy sediment, sparse vegetation, sudden and intense rainfall, strong winds, and aridity. Despite their nebulous definition, the badlands at Badlands NP have come to be seen as the archetypical badlands due to their size and extent (also thanks to a bit of good timing in their discovery by white men). Incidentally, the name “bad land” has no complicated etymology – that exact phrase, or a slight variation thereof, was historically applied to this terrain by Lakota, French trappers, and English-speaking explorers alike. The same properties that allow for the creation of badlands mean the land isn’t conducive to transport, farming, or habitation, and isn’t a good source of water or oil. Badlands are an excellent source for fossil exposure, however, and are highly valued by paleontologists. Badlands NP, in fact, is worthy of its designation not only for its natural beauty and geologic record, but also for its rich fossil fauna (but more on that later). </span></p><span style="font-size:100%;"> </span><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixg7KfTHh5U6FWFlfGo-pwFzw97NTl1xlmE13xUka8603ddg0otCeTtIZ6wm0BsQc_JbFveJ9KT1JFKprPYTj4iTZ8X634Cn1bRWD-Z76xDpAT_6c486WS21X39s0qXFF3D-gglZG2GUs/s1600/IMG_1248.JPG"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 320px; height: 240px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixg7KfTHh5U6FWFlfGo-pwFzw97NTl1xlmE13xUka8603ddg0otCeTtIZ6wm0BsQc_JbFveJ9KT1JFKprPYTj4iTZ8X634Cn1bRWD-Z76xDpAT_6c486WS21X39s0qXFF3D-gglZG2GUs/s320/IMG_1248.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5478007553320124274" /></a><p class="MsoNormal"><span style="font-size:100%;">In Badlands NP, the “loose sediment” is over 150 m of volcaniclastic sediment, blown into western South Dakota from eruptions in Nevada and Utah(see Larson and Evanoff, 1998), and fluvially transported into the park between 32 and 28 Ma (Oligocene). Collectively, this sediment composes the Brule Formation, which makes up the bulk of the rugged, colorful badlands seen in the park. As it turns out, the famous colors of the badlands are significant - color banding of rocks in places like Grand Canyon and </span><st1:place st="on"><st1:placename st="on"><span style="font-size:100%;">Canyonlands</span></st1:placename><span style="font-size:100%;"> </span><st1:placetype st="on"><span style="font-size:100%;">National Parks</span></st1:placetype></st1:place><span style="font-size:100%;"> are a result of sediment deposited in very different environments, representing different formations. The color banding in Badlands NP is largely confined to one formation, and is caused by paleosols, or fossilized soils (Retallack, 1983). In the picture to the left, for example, the different red, white, and grey bands, as well as the thinner bands sticking out as ledges, represent different paleosols (the brown stakes at the bottom left are 1 m tall, for scale). As can be seen in the picture below, these paleosols can be found </span><i style="mso-bidi-font-style: normal"><span style="font-size:100%;">ad nauseum </span></i><span style="font-size:100%;">in outcrops – in one area, Retallack (1983) found 87 separate paleosols in a 143 m stratigraphic section. Taphonomically, paleosols are great because they represent surface exposure, can indicate the paleoenvironment, and can even hint at whether fossils may be present. But that’s only if you know how to read them, which as I’m learning, is not at all easy (the banding you see on the surface of the badlands, for instance, may have little to do with the actual banding in the rock underneath). Anyways, much more to come…</span></p><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEja6D0SFde951kYN0C8_ooxeABFjwzKH-nKK1vln0dkKdeawIOWuVsHfycrxfQjKGgTTi8LqSKHTwAQxaqkuuBsQcc_ZKTygqSWjLXvwBBRZ6Jch8yCLZWhlzkpcdSMXTTCC6aa9tZdWtI/s1600/IMG_1250.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 300px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEja6D0SFde951kYN0C8_ooxeABFjwzKH-nKK1vln0dkKdeawIOWuVsHfycrxfQjKGgTTi8LqSKHTwAQxaqkuuBsQcc_ZKTygqSWjLXvwBBRZ6Jch8yCLZWhlzkpcdSMXTTCC6aa9tZdWtI/s400/IMG_1250.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5478009454617166546" /></a> <p class="MsoNormal"><o:p> </o:p></p> <p class="MsoNormal"><span style="font-size:78%;">REFS</span></p><span style="font-size:78%;"> </span><p class="MsoNormal"><span style="font-size:78%;">Larson, E.E., and Evanoff, E. 1998. Tephrostratigraphy and sources of the tuffs of the </span><st1:place st="on"><span style="font-size:78%;">White River</span></st1:place><span style="font-size:78%;"> sequence, </span><i style="mso-bidi-font-style:normal"><span style="font-size:78%;">in</span></i><span style="font-size:78%;"> Terry, D.O., Jr., LaGarry, H.E., and Hunt, R.M., eds., Depositional environments, lithostratigraphy, and biostratigraphy of the White River and Arikaree Groups (Late Eocene to Early Miocene, North America): Geological Society of America Special Paper 325, p. 1-14).</span></p><span style="font-size:78%;"> </span><p class="MsoNormal"><span style="font-size:78%;">Retallack, G.J. 1983. Late Eocene and Oligocene paleosols from </span><st1:place st="on"><st1:city st="on"><span style="font-size:78%;">Badlands National Park</span></st1:city><span style="font-size:78%;">, </span><st1:state st="on"><span style="font-size:78%;">South Dakota</span></st1:state></st1:place><span style="font-size:78%;">: Geological Society of America Special Paper 193, 82 p.</span></p>Benjamin Scherzerhttp://www.blogger.com/profile/06017783834589973483noreply@blogger.com0tag:blogger.com,1999:blog-9147223320739722188.post-10452490335032140682010-03-10T12:59:00.000-08:002010-03-10T14:02:43.104-08:00The Awesomeness of Beecher's Trilobite Bed<span style="font-size:130%;">Trilobites are remarkable animals, deserving not only multiple posts, but probably their own blog (if one exists, I haven’t found it yet…). They are one of the most abundant, well-known, and best-studied organisms from the fossil record. If anyone goes through a “rockhound” period in his or her life, it’s almost a guarantee they picked up a fossil trilobite. For those unfamiliar, trilobites kind of looked like a cross between a pill bug and cockroach (see below), but lived in the ocean. However, 99% of the time, it’s just the exoskeleton of trilobites that is preserved. For better preservation, there are two prime trilobite fossil beds in the world, the Hunsrück Shale of <st1:country-region st="on">Germany</st1:country-region>, and <st1:city st="on">Beecher</st1:city>’s Trilobite Bed in <st1:state st="on"><st1:place st="on">New York</st1:place></st1:state>.</span><p class="MsoNormal"><st1:city st="on"><st1:place st="on"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgs50cPMz6JO04BiWR4QixLQ2-vDKxSF8j8TZUUzAdkLc9mwH93suWWlmdcssENB0YHdv6MtPcdlfxFVnGWweCMBbA01ZKBq2_Q2xEcNZ5RyBf_RECAmSmQZjGAwX2Eo7_lR2iN5Eqcj6w/s1600-h/Pic1Current.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 200px; height: 142px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgs50cPMz6JO04BiWR4QixLQ2-vDKxSF8j8TZUUzAdkLc9mwH93suWWlmdcssENB0YHdv6MtPcdlfxFVnGWweCMBbA01ZKBq2_Q2xEcNZ5RyBf_RECAmSmQZjGAwX2Eo7_lR2iN5Eqcj6w/s200/Pic1Current.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5447121752481402050" /></a><span style="font-size:100%;">Beecher</span></st1:place></st1:city><span style="font-size:100%;">’s Trilobite Bed is the result of a </span><a href="http://oceanservice.noaa.gov/facts/turbidity.html"><span style="font-size:100%;">turbidity flow</span></a><span style="font-size:100%;"> (think an underwater “mudslide” of very muddy water, image at left from </span><a href="http://www.nr.no/pages/sand/area_res_char_tumod"><span style="font-size:100%;">here</span></a><span style="font-size:100%;">) which picked up trilobites, carried them a short distance, and essentially buried them alive. For taphonomic reasons, this rapid burial exquisitely fossilized the trilobites as pyrite, fossilizing not only exoskeletons but legs, antennae, muscles, and even internal organs (image below from PDF </span><a href="http://www.yale.edu/yibs/YEN%20Fall%202007.pdf"><span style="font-size:100%;">here</span></a><span style="font-size:100%;">). For a more lengthy explanation of how </span><st1:city st="on"><st1:place st="on"><span style="font-size:100%;">Beecher</span></st1:place></st1:city><span style="font-size:100%;">’s Trilobite Bed was formed, there’s an excellent chapter by Etter (2002), and Cisne’s original taphonomic study from 1973 is now </span><a href="http://peabody.research.yale.edu/scipubs-search/"><span style="font-size:100%;">publicly available</span></a><span style="font-size:100%;">. But the </span><st1:city st="on"><st1:place st="on"><span style="font-size:100%;">Beecher</span></st1:place></st1:city><span style="font-size:100%;"> bed is a definite taphonomic outlier for a couple reasons, both of which probably need a brief introduction:</span><span style="mso-spacerun:yes"><span style="font-size:100%;"> </span></span><span style="mso-tab-count:1"><span style="font-size:100%;"> </span></span></p><span style="font-size:100%;"> </span><p class="MsoNormal"><b style="mso-bidi-font-weight:normal"><span style="font-size:100%;">Trilobites were rebels before it was cool </span></b></p><p class="MsoNormal"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1Q2FSikKnUjXDgmnPWZhbolETeTF7iUuRtdq69yaBqSG-jSWHG8NrBbt6mpK1C7alJr0mMa16n6Twx3ymBckKVYMwlm2E7St9UcIVCxJnalvys8dHv_ywJhb9pddwNLtoawlZ2fIUEPQ/s1600-h/trilobite.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 248px; height: 159px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1Q2FSikKnUjXDgmnPWZhbolETeTF7iUuRtdq69yaBqSG-jSWHG8NrBbt6mpK1C7alJr0mMa16n6Twx3ymBckKVYMwlm2E7St9UcIVCxJnalvys8dHv_ywJhb9pddwNLtoawlZ2fIUEPQ/s320/trilobite.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5447123262856285618" /></a><span style="font-size:100%;">First, in the ocean, only three things are needed to produce pyrite (iron sulfide: FeS</span><span style="font-size:100%;"><span style="'font-family:;font-size:12.0pt;"><sub>2</sub>)</span></span><span style="font-size:100%;">: sulfur, iron, and organic carbon. Chemical studies of the </span><st1:city st="on"><st1:place st="on"><span style="font-size:100%;">Beecher</span></st1:place></st1:city><span style="font-size:100%;"> bed (Briggs et al., 1991) suggest the seawater was already rich in sulfur and iron – all that was needed was organic carbon, readily provided by the washed-in trilobites. Due to the abundance of sulfur and iron, it is plausible that </span><i style="mso-bidi-font-style:normal"><span style="font-size:100%;">every</span></i><span style="font-size:100%;"> trilobite (as in, 100%) washed in by the turbidity flow acted as a nucleation site for pyrite and ended up getting fossilized. This is highly unusual – preserving 10% of a paleo-environment would make a paleontologist drool (personal observation).</span></p><span style="font-size:100%;"> </span><p class="MsoNormal"><span style="font-size:100%;">Second, pyrite</span><span style="font-size:100%;"> can form two ways in the ocean: through “bacterial sulfate reduction” (BSR) or through </span><a href="http://scienceray.com/earth-sciences/geology/turning-sediments-into-rock-diagenesis-geology/"><span style="font-size:100%;">diagenesis</span></a><span style="font-size:100%;"> (after burial). BSR occurs in open seawater, while diagenesis occurs in the seabed sediment, with no contact with the seawater above. How the pyrite is derived affects the sulfur </span><a href="http://en.wikipedia.org/wiki/Isotope"><span style="font-size:100%;">isotopes</span></a><span style="font-size:100%;"> in the mineral: it is commonly thought that BSR-derived pyrite is enriched in “lighter” </span><sup><span style="font-size:100%;">32</span></sup><span style="font-size:100%;">S, while diagenetic pyrite is enriched in “heavier” </span><sup><span style="font-size:100%;">34</span></sup><span style="font-size:100%;">S. Understandably, soft parts (like legs and antennae) decompose faster than hard parts (like exoskeletons), so soft parts would need to fossilize first, right? Well, as it turns out, the legs and antennae of the Beecher trilobites tend to be enriched in the “heavier” </span><sup><span style="font-size:100%;">34</span></sup><span style="font-size:100%;">S, while the exoskeletons are enriched in the “lighter” </span><sup><span style="font-size:100%;">32</span></sup><span style="font-size:100%;">S (Briggs et al., 1991). This suggests the exoskeletons were fossilized first, </span><i style="mso-bidi-font-style:normal"><span style="font-size:100%;">before</span></i><span style="font-size:100%;"> burial, and the softer parts stuck around and were fossilized </span><i style="mso-bidi-font-style: normal"><span style="font-size:100%;">after</span></i><span style="font-size:100%;"> burial. This is kind of like a root beer float where the root beer evaporates before the ice cream even melts. Briggs et al hypothesized this could have occurred due to changes in water chemistry as the exoskeleton decomposed, but there could be a greater disturbance in the force...</span></p><span style="font-size:100%;"> </span><p class="MsoNormal"><b style="mso-bidi-font-weight:normal"><span style="font-size:100%;">Wait, what do you mean “</span><i style="mso-bidi-font-style:normal"><span style="font-size:100%;">it is commonly thought</span></i><span style="font-size:100%;">”?</span><span style="mso-spacerun:yes"><span style="font-size:100%;"> </span></span><span style="mso-spacerun:yes"><span style="font-size:100%;"> </span></span></b></p><span style="font-size:100%;"> </span><p class="MsoNormal"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJ30f8IcgMR9uEti6_nCA-RFcriXGy-WNGHBRcT2VgzQ-tN5xST8bly0pQarZ2zKeAhm2Ifjje3hiUidccU5MFiq9LTWQ5otcyQ0pEAGISAFejos3o-DWvGjXs8KSA7WJuNgw-GU0qUhM/s1600-h/rocks2-300x259.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 300px; height: 259px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJ30f8IcgMR9uEti6_nCA-RFcriXGy-WNGHBRcT2VgzQ-tN5xST8bly0pQarZ2zKeAhm2Ifjje3hiUidccU5MFiq9LTWQ5otcyQ0pEAGISAFejos3o-DWvGjXs8KSA7WJuNgw-GU0qUhM/s320/rocks2-300x259.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5447122945656786050" /></a><span style="font-size:100%;">The paradigm on sulfur isotopes, as it turns out, was recently challenged by a publication in </span><a href="http://geology.gsapubs.org/"><span style="font-size:100%;">Geology</span></a><span style="font-size:100%;"> led by </span><a href="http://marine.unc.edu/people/Faculty/ries"><span style="font-size:100%;">Justin Ries</span></a><span style="font-size:100%;">, a marine geologist at The University of North Carolina (pictured in the field at left, from </span><a href="http://www.climateshifts.org/?p=2560"><span style="font-size:100%;">here</span></a><span style="font-size:100%;">). Ries and colleagues examined the sulfur isotopes in a 10 million-year stretch of carbonates from </span><st1:country-region st="on"><st1:place st="on"><span style="font-size:100%;">Namibia</span></st1:place></st1:country-region><span style="font-size:100%;"> (Ries, 2009: PDF available at link above). They found that the pyrite derived by BSR was actually enriched in the </span><i style="mso-bidi-font-style:normal"><span style="font-size:100%;">heavier</span></i><span style="font-size:100%;"> </span><sup><span style="font-size:100%;">34</span></sup><span style="font-size:100%;">S isotope, enough to be labeled “superheavy pyrite.” Needless to say, this throws a monkey wrench into the current notion that the bacterially-derived pyrite should be “lighter.”</span></p><span style="font-size:100%;"> </span><p class="MsoNormal"><span style="font-size:100%;">The translation of this article towards the </span><st1:city st="on"><span style="font-size:100%;">Beecher</span></st1:city><span style="font-size:100%;"> bed is uncertain – Ries et al attribute the anomalous pyrite isotopes to large-scale (possibly global) low atmospheric oxygen, but it is unlikely such conditions existed when the </span><st1:city st="on"><st1:place st="on"><span style="font-size:100%;">Beecher</span></st1:place></st1:city><span style="font-size:100%;"> bed was deposited. They also consider the anomalous pyrite could have resulted from stratification of the water column, low water levels, or aerobic reoxidation (mixing oxygen back into the water). Personally, I could easily be convinced that turbidity flows, like the kind that produced the </span><st1:city st="on"><st1:place st="on"><span style="font-size:100%;">Beecher</span></st1:place></st1:city><span style="font-size:100%;"> bed, could carry oxygenated water. But, to my knowledge, it’s uncertain how the isotopes of subsequent diagenetic pyrite would be effected – i.e., could it end up being “lighter” than the bacterially-derived pyrite, or would it be “super-duper heavy”? Like any good scientific study, it creates more questions than it answers… </span></p> <p class="MsoNormal"><o:p> </o:p></p> <p class="MsoNormal"> <p class="MsoNormal"><strong><span style="font-size:85%;">REFS</span></strong></p><span style="font-size:85%;"> </span><p class="MsoNormal"><span style="font-size:85%;">Briggs, D.E.G., Bottrell, S.H., and Raiswell, R., 1991, Pyritization of soft-bodied fossils: Beecher’s Trilobite Bed, Upper Ordovician, New York State, Geology, v. 19, p. 1221–1224. </span></p><span style="font-size:85%;"> </span><p class="MsoNormal"><span style="font-size:85%;">Cisne, J.L., 1973, </span><st1:city st="on"><st1:place st="on"><span style="font-size:85%;">Beecher</span></st1:place></st1:city><span style="font-size:85%;">’s Trilobite Bed revisited: ecology of an Ordovician deepwater fauna, Postilla, v. 160, p. 1–25.</span></p><span style="font-size:85%;"> </span><p class="MsoNormal"><span style="font-size:85%;">Etter, W., 2002, Beecher’s Trilobite Bed: Ordovician pyritization for the other half of the trilobite, </span><i style="mso-bidi-font-style: normal"><span style="font-size:85%;">in</span></i><span style="font-size:85%;"> Bottjer, D.J., Etter, W., Hagadorn, J.W., and Tang, C.M., eds, Exceptional Fossil Preservation: a Unique View on the Evolution of Marine Life, Columbia University Press, New York, p. 131–142.</span></p><p class="MsoNormal"><span style="font-size:85%;">Ries, J.B., Fike, D.A., Pratt, L.M., Lyons, T.W., and Grotzinger, J.P., 2009, Superheavy pyrite (δ</span><sup><span style="font-size:85%;">34</span></sup><span style="font-size:85%;">S</span><sub><span style="font-size:85%;">pyr</span></sub><span style="font-size:85%;"> > δ</span><sup><span style="font-size:85%;">34</span></sup><span style="font-size:85%;">S</span><sub><span style="font-size:85%;">CAS</span></sub><span style="font-size:85%;">) in the terminal Proterozoic Nama Group, southern Namibia: a consequence of low seawater sulfate at the dawn of animal life, Geology, v. 37, p. 743–746.</span><span style="font-size:85%;"> </span></p>Benjamin Scherzerhttp://www.blogger.com/profile/06017783834589973483noreply@blogger.com1tag:blogger.com,1999:blog-9147223320739722188.post-1044461884625391472010-02-28T14:10:00.000-08:002010-03-01T16:37:48.505-08:00How to Get a Head in Paleontology<div><div><span class="Apple-style-span" style="font-size:large;">One of the most fundamental aspects of taphonomy is that of "taphonomic loss" - the loss of information through taphonomic processes. Perhaps the most common form of taphonomic loss is loss of the actual fossils, including organisms whose remains become fossilized but never found, and those organisms whose remains are never even fossilized. A recurring theme in vertebrate taphonomy is that not all bones are equal, even within the same animal. It's not a particularly insightful rule, but it has plenty of consequences. </span><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><b><span class="Apple-style-span" style="font-size:medium;">If it weren't attached...</span></b></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;">I've heard or overheard comments from several invertebrate paleontologists, and even an invertebrate taphonomist or two, on the tendency of dinosaur fossils to be found without any cranial material. It's a understandable impression to develop, but it actually sells many dinosaur taxa short. Among ceratopsians ("horned dinosaurs") and pachycephalosaurs ("dome-headed dinosaurs"), cranial material can be the most common material found, and according to Horner et al (2004), "[c]omplete skulls are known for nearly all of the genera and species of hadrosaurids [<i>ed-"duckbilled dinosaurs"</i>], and virtually every established hadrosaurid taxon is based on at least some cranial material." (one catch to the latter is the fact that many hadrosaurid taxa are identified predominantly by cranial features, but regardless...) One dinosaur taxa that is known for a lack of cranial material, however, is the sauropods.</span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHvbxIHVuTgA5SGclDxUwzujeoRqHT7pgUthKJ3VQGWgMtS1YLYvRXtMiMiEoq32yH1p1ukv8MqzoYAJBXlztSTQWDUxS9ZyZTqqiBGwpJfoT9uPMCFuivOCQ9FYcfmykhhHmFRz-g_EI/s1600-h/l-mhettwer-psereno-niger-15.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 320px; height: 148px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHvbxIHVuTgA5SGclDxUwzujeoRqHT7pgUthKJ3VQGWgMtS1YLYvRXtMiMiEoq32yH1p1ukv8MqzoYAJBXlztSTQWDUxS9ZyZTqqiBGwpJfoT9uPMCFuivOCQ9FYcfmykhhHmFRz-g_EI/s320/l-mhettwer-psereno-niger-15.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5443423723104310466" /></a>Sauropods are an especially popular taxa of dinosaurs, famous for attaining body sizes unparalleled among other land animals. Not surprisingly, this leads to an extreme variety in bone size. As the image on the left illustrates (from <a href="http://www.baystatereplicas.com/dinosaur_bones.htm">here</a>), it is not uncommon for sauropod limb bones to reach or exceed the size of an average truck driver. But also worth noting is the skull of the bizarre sauropod </span></span><i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0001230"><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;">Nigersaurus</span></span></a></i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0001230"><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"> </span></span></a><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;">to the left (from <a href="http://scienceblogs.com/laelaps/2007/11/nigersaurus_taqueti.php">here</a>), with the head of discoverer Paul Sereno to scale. For their size, sauropods had small heads, and some of their cranial bones were no larger or stronger than ours (non-homologously, of course). In fact, some of the cranial bones of the pictured Nigersaurus are </span></span><a href="http://ngm.nationalgeographic.com/2007/12/bizarre-dinosaurs/nigersaurus-text"><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;">"as thin as a paper plate."</span></span></a><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"> For the same reason you don't wash your lingerie with your denim coveralls, it's rare for a taphonomic mode to preserve both delicate cranial material and limb bones the size of tree trunks. Consequently, sauropod skulls remain a relatively rare find - the "recent" discovery of two complete sauropod skulls in Utah, for instance, was significant enough to make </span></span><a href="http://news.yahoo.com/s/ap/20100223/ap_on_re_us/us_dinosaur_discovery"><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;">headlines</span></span></a><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;">.</span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"><b>Definitely not ready to travel</b></span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;">Sauropods are remarkable animals for a variety of reasons, some of which are more infamous than famous. One reason which certainly qualifies as one of the former is the hypothesis that sauropods had trunks like modern elephants. There are many reasons not to believe this notion, and accomplished Scienceblogger Darren Naish has done as excellent job summarizing these reasons </span></span><a href="http://scienceblogs.com/tetrapodzoology/2009/03/junk_in_the_trunk.php"><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;">here</span></span></a><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;">. However, I would like to expand on one line of attack Naish presents. In discussing the cranial musculature associated with trunks, Naish points out:</span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"><blockquote><span class="Apple-style-span" style="font-family:arial;">[B]ig, strong muscles like those involved in any hypothetical trunk leave visible attachment sites, such as crests, scars, or fossae. These sorts of structures are obvious in extant trunked mammals... They are entirely absent in the skulls of sauropods.</span></blockquote></span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;">Which is entirely true, but...these features might be lost or difficult to identify if the bones are poorly preserved or exhibit significant surface alteration. Fortunately, there is also associated evidence inside the bone.<br /></span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkgUOja3Mjf3S_s_CWRmGHlA7X3NP4DDowUqQ-cKy8OpmIuJndEb7EqljFpCHQJjzpoGoK56ICpR_EwgoEcQiEMKCwnbED3TASU4ocJw9Le8FrZYKUDatAIDyLbglRfj4Wk8JnudUq0II/s1600-h/sharpey2.jpg"><img style="float:left; margin:0 10px 10px 0;cursor:pointer; cursor:hand;width: 288px; height: 400px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjkgUOja3Mjf3S_s_CWRmGHlA7X3NP4DDowUqQ-cKy8OpmIuJndEb7EqljFpCHQJjzpoGoK56ICpR_EwgoEcQiEMKCwnbED3TASU4ocJw9Le8FrZYKUDatAIDyLbglRfj4Wk8JnudUq0II/s400/sharpey2.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5443424641079794402" /></a>Most fossil bone, as it turns out, hasn't just been converted into a bone-shaped rock. Original bone and cellular structure is often preserved, and cutting the bone into thin sections (thin: 20-120 micrometers) can make these features visible, as seen to the left, above (image from </span></span><a href="http://www.geo.ucalgary.ca/~macrae/t_origins/carbbones/dinobone.html"><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;">here</span></span></a><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;">). This is the basis behind the field of paleohistology. One such structure is "Sharpey's fibers": these are the numerous dark, sub-horizontal "dashes" to the left, below (titanosaur scute, from Chinsamy-Turan, 2005). Sharpey's fibers are basically the remnants of collagen fibers where some structure (tendon, skin, horn, etc) was anchored to the bone. If an animal had, for instance, a trunk, there would be abundant Sharpey's fibers in the bones where the "trunk muscles" were anchored.</span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"><br /></span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><b><span class="Apple-style-span" style="font-size:medium;">What are we waiting for?</span></b></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"><br />After all, Sharpey's fibers are fairly easy to identify - even a grad student could handle this type of hypothesis testing. Unfortunately, my proposal has its own flaws. Even after making the thin sections, there's no guarantee the histological features won't have been obliterated by other processes (bacterial invasion, permineralization). And as it turns out, bacterial invasion is particularly common in cranial bones (Horner, personal comm). You may also remember my comment about how sauropod skull material is "rare," and how making thin sections involves "cutting." Not surprisingly, those repositories lucky enough to house sauropod cranial material are reluctant enough to allow access to it, let alone hand it out to be sliced up like deli meat, with the chance that there will be no appreciable data gained in the end.</span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><br /></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdaRP4mxDwYRLSmQOgU0IlwDQ7l0zrzirlHrI5VCmRRm00z6LKKkIkAgy3dntpzLhBYX8uerKYuIn3QuFH4yeWxK7P6UfptGHcIeLY8kv6i3vbs4y-zY1SDPY50lcHkyaXaOHjgxsbuGc/s1600-h/horse.jpg"><img style="text-align: left;display: block; margin-top: 0px; margin-right: auto; margin-bottom: 10px; margin-left: auto; cursor: pointer; width: 400px; height: 225px; " src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdaRP4mxDwYRLSmQOgU0IlwDQ7l0zrzirlHrI5VCmRRm00z6LKKkIkAgy3dntpzLhBYX8uerKYuIn3QuFH4yeWxK7P6UfptGHcIeLY8kv6i3vbs4y-zY1SDPY50lcHkyaXaOHjgxsbuGc/s400/horse.jpg" border="0" alt="" id="BLOGGER_PHOTO_ID_5443425209128877410" /></a></span></span></div><div style="text-align: center;"><i><span class="Apple-style-span" style="font-size:x-small;">"Hey, thanks for letting us borrow your horse! Unfortunately, all of our tests were inconclusive..."</span></i></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-family:Georgia, serif;"><br /></span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><b><span class="Apple-style-span" style="font-size:small;">REFS--</span></b></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:small;"><br /></span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:small;">Chinsamy-Turan, A. 2005. The microstructure of dinosaur bone: deciphering biology with fine-scale techniques, Johns Hopkins University Press, Baltimore: 216 p. </span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:small;"><br /></span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style="font-size:medium;"><div><span class="Apple-style-span" style="font-size:small;">Horner, J.R., Weishampel, D.B., and Forster, C.A. 2004. Hadrosauridae, </span><i><span class="Apple-style-span" style="font-size:small;">in </span></i><span class="Apple-style-span" style="font-size:small;">Weishampel, D.B., Dodson, P., and Osmólska, H., eds, The Dinosauria, 2nd edition, University of California Press, Berkeley: pp. 438-463.</span></div></span></span></div><div><span class="Apple-style-span" style="font-family:'times new roman';"><span class="Apple-style-span" style=" ;font-size:medium;"><br /></span></span></div></div></div></div>Benjamin Scherzerhttp://www.blogger.com/profile/06017783834589973483noreply@blogger.com0tag:blogger.com,1999:blog-9147223320739722188.post-942446150900321042010-02-27T19:23:00.000-08:002010-02-27T20:02:29.538-08:00Welcome to the Blog<a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNwM1uml4uwRwPNA-unzGh1iFXDQ5Hy5YBecXV24nj8Um3BP5W19ekSGO1p00tLT4Z62kJ6QsTExl_d1ZHxCeO1mED3WROJmT3OHid7lRUiTQBMziPnwXvAxxX3Jx0xfX-mOSVpE7Zntc/s1600-h/UNTITL~1.JPG"><img style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;width: 400px; height: 191px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiNwM1uml4uwRwPNA-unzGh1iFXDQ5Hy5YBecXV24nj8Um3BP5W19ekSGO1p00tLT4Z62kJ6QsTExl_d1ZHxCeO1mED3WROJmT3OHid7lRUiTQBMziPnwXvAxxX3Jx0xfX-mOSVpE7Zntc/s400/UNTITL~1.JPG" border="0" alt="" id="BLOGGER_PHOTO_ID_5443131486192475442" /></a>Hello, and welcome to "A Field of Mud and Bone." This blog will attempt to cover the vast and intriguing intersection of vertebrate taphonomy (predominantly dinosaurs) and sedimentology. Taphonomy is a rapidly growing field in vertebrate paleontology, while sedimentology is one that has historically struggled for proper recognition. I will try to vigilantly track the former while giving the latter its due. But first, introductions:<div><br /></div><div>- My primary goal is to publicize aspects of vertebrate paleontology and sedimentology that are particularly fascinating or neglected. Both of these fields are broad, and occasional posts of a strictly biologic or geologic focus will occur. Posts focused on other scientific fields, or even outside of science, will try to be kept to a minimum, and will hopefully be at least tangentially related to vert paleo and seds. But there's just so much cool stuff to talk about....</div><div><br /></div><div>- The title of this blog comes from the Bruce Springsteen song "Devils & Dust." The song is about the travails of soldiers in the Iraq War, but the phrase is perfectly fitting for vertebrate taphonomy. </div><div><br /></div><div>- In the end, I am admittedly still a halfway developed graduate student. If someone out there has already written about something I post, responses of <i>"Hey, dummy, you ever read (insert reference here)?"</i> may not be enjoyed, but they will probably be valued.<br /><div style="text-align: left;"><span class="Apple-style-span" style="color:#0000EE;"><u><br /></u></span></div><br /><div style="text-align: center;"><br /></div></div>Benjamin Scherzerhttp://www.blogger.com/profile/06017783834589973483noreply@blogger.com1