New Papers on a Plane

["Jerry D. Harris" <jharris@dixie.edu>]

Andrew R.C. Milner came up with that subject line (!), and SP oriented me 
toward some of the papers below.  And we all know what happens when paleo 
papers get loose in small, confined spaces...

None of these directly pertain to dinosaurs, but I thought they'd be of 
interest to some on the list!  First, a couple of popular articles (in 
Spanish); they have quite excellent illustrations:


Apesteguía, S. 2007. La evolución de los lepidosaurios. Investigación y 
Ciencia 367:54-63.


Apesteguía, S. 2007. Lepidosaurios en movimiento: de los lagartos a las 
serpientes. Investigación y Ciencia 371:55-61.



More on the Chicxulub impact:

Wittmann, A., Kenkmann, T., Hecht, L., and Stöffler, D. 2007. Reconstruction 
of the Chicxulub ejecta plume from its deposits in drill core Yaxcopoil-1. 
Geological Society of America Bulletin 119(9):1151-1167. doi: 
10.1130/B26116.1.

ABSTRACT: Formation conditions of suevite-like impactites from an 100 m 
thick drill core sequence through the Cretaceous-Tertiary Chicxulub crater 
were reconstructed from empirical data obtained by petrologic and image 
analytical methods. The temporal evolution of the cratering process from the 
initial stage of excavation to the collapse of the ejecta plume is evidenced 
by the petrographic characteristics and modal composition of the suevitic 
rocks, including the size distribution and shape parameters of melt 
particles. Emplacement of the lowermost suevitic deposits likely started in 
the first minute after the impact by the passing ejecta curtain that 
interacted with the expanding ejecta plume. These ejecta deposits were 
capped by a tongue of coherent impact melt that was transported outward from 
the crater center during the collapse of the central uplift 5 min after 
impact. On top of this brecciated impact melt rock, the collapsing ejecta 
plume deposited air-fall suevites. The basal air-fall unit, Middle Suevite, 
may have been deposited due to a density current-like clumping of hot 
debris. With progressive cooling, regions of the ejecta plume were entrained 
in its collapse that produced vapor condensates, accretionary rims, and 
different oxygen fugacities. After cooling progressed, atmospheric 
conditions began to reestablish over the crater and turbulence decreased, 
supposedly after the first 10 min of initial ejecta plume collapse. This led 
to a winnowing out of fine matrix material and distinct sorting. However, 
due to aquatic reworking, only material that was deposited until 1 h after 
cessation of turbulent atmospheric conditions was retained.



And lastly, a fun little paper documenting that yes, at least some 
crocodylians shed "tears" while eating (and doing some other activities, 
too), at least some of the time:


Shaner, D.M., and Vliet, K.A. 2007. Crocodile tears: and thei eten hem 
wepynge. Bioscience Journal 57(7):615-617. doi: 10.1641/B570711.

ABSTRACT: Whether crocodiles shed tears while eating has been fodder for 
fable and controversy for hundreds of years. We present the first 
unequivocal evidence that crocodilians lacrimate during meals and that they 
do so in a peculiar fashion.


I never knew that this tearing action had a technical name, but it's a 
fabulous one:  prandial lacrimal ebullition.  Gonna hafta use that one 
sometime...  (Reminds me of Dr. McCoy's excuse for getting in to the 
hospital room to rescue Chekov in "Star Trek IV," wheeling a moaning Dr. 
Gillian Taylor on a gurney into an operating room:

KIRK: Out of the way!

GUARD: Sorry, Doctor, I have strict orders...

[Gillian moans in pain]

McCOY: My God man. Do you want an acute case on your hands? This woman has 
immediate post-prandial, upper-abdominal distention!

[they enter the OR]

KIRK: What did you say she has?

McCOY: Cramps. )

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jerry D. Harris
Director of Paleontology
Dixie State College
Science Building
225 South 700 East
St. George, UT  84770   USA
Phone: (435) 652-7758
Fax: (435) 656-4022
E-mail: jharris@dixie.edu
and     dinogami@gmail.com
http://cactus.dixie.edu/jharris/

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