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Re: Bigass volcanism (was RE: Human bottlenecks and bird taxonomy (was: Re: "Dinosaurs Died Within Hours...))



Weren't the Siberian Traps the largest known volcanic eruption ever? I recently read that the amount of lava flow could have covered the entire surface of the earth under 10ft. of lava if spread evenly. The Siberian Traps eruption is considered one of the key players in the Great Dying.

http://palaeo.gly.bris.ac.uk/Palaeofiles/Permian/SiberianTraps.html
http://www.rochester.edu/pr/releases/ear/basu2.htm

James

Thomas R. Holtz, Jr. wrote:

From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
Eric Martichuski



Within the past 450 million years, we know of only one eruption


that was


larger.


Which was that?


I honestly don't know. That's just what one particular article said. (I
know, I know: _bad_ scholar, no cookie!)



Presumably the giant eruption during the Ordovician that produced the Millbrig Beds of North America and the Big Bentonite of Europe.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796




-----Original Message-----





We see human "races" in the fossil record!?! This is total news to me...
sure, 50 years ago everyone thought so, but that was dropped.


Well, I did put "race" in quotations.  How about "regional phenotypic
differences in cranial osteology?"  I know the "multiple origins"
theory of
human evolution relies on supposed observations of just such differences
(I'm not convinced the theory is valid, but it's hardly 50 years old and
totally outdated).  The volcanic bottleneck idea says that such
differences
were selected and amplified through the umpteen different tiny "founder
effect" populations Toba's eruption created in a single "instant".



Interesting. Do any other species show evidence for such a bottleneck at
that time?


According to a book called "Tears of the Cheetah", which has a
bunch of neat
anecdotes about the combination of genetics with wildlife
biology/conservation, both cougars and cheetahs show similar
indications of
bottlenecks (which I _believe_ are dated to the same basic time period.
It's been a few months since I read the book, though).  The cheetah
bottleneck _may_ be more recent, or it may just have been exacerbated
recently.  At the moment, any random cheetah can accept skin
grafts from any
other cheetah with no risk of rejection.  And the cougar bottleneck is in
North American cougars which apparently all spring from Central American
stock after the original nothern populations were wiped out (by ice age
activity, IIRC).  Possibly Toba related, but I just can't recall
the dates,
sorry.

Thanks for the clarifications about vultures, btw.  I hadn't
_thought_ they
were somehow taxonomically "special", but it's not as familar a
subject for
me as others.

Eric
______________________________________________________________________
"There is no other wisdom,
And no other hope for us
But that we grow wise. -- Diane Duane
______________________________________________________________________

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