[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
New Papers on a Plane
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
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:
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
225 South 700 East
St. George, UT 84770 USA
Phone: (435) 652-7758
Fax: (435) 656-4022
STORIES IN SIX WORDS OR LESS:
"Machine. Unexpectedly, I'd invented
-- Alan Moore
"Easy. Just touch the match to"
-- Ursula K. Le Guin
"Batman Sues Batsignal: Demands
-- Cory Doctorow