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Re: Deccan Traps and Fried Dinos



On Sun, 22 Feb 1998 15:54:23 -0800 Stanley Friesen <sarima@ix.netcom.com>
writes:

>Flood type eruptions, however, had not occurred for many millions of 
>years previously.  And the Deccan Traps are second only to the
>Siberian Traps (of the Permo-Triassic boundary) in volume.


And third in aerial- and volume-extent is the Columbia Plateau
Basalt Group of the Pacific Northwest of North America
(late middle Miocene through latest Miocene).


>So, it is not merely the fact of volcanic eruptions, it is the 
>existence of a *temporally* *rare*, unusually voluminous type
>of eruptions across the boundary.

True, but keep in mind that these flood basalt regions didn't
erupt all at once. In fact, there was a vastly greater intervening
time during which these fissures weren't erupting at all.
The Deccan Traps are composed of many individual flows which
are often separated by sedimentary layers containing...uhh...
...dinosaurs.

In the Columbia Plateau, similar sedimentary interbeds are found,
and these thin units contain a rather rich assemblage of mammals and
plants.  As far as I am aware, no large numbers of extinctions in the
Pacific Northwest of North America have been specifically
tied to the eruptions of the Columbia Flood Basalts.

So, if one had a time machine, and travelled to India during the
middle of "Deccan Time", your chances of landing there during the
middle of one of the many eruption events is practically zero.
But you would have an excellent chance of seeing a titanosaur
walking around on the fern-covered lava plains.


Since the Deccan Traps span the K/T Boundary, and since the
Cretaceous half of the Traps contain abundant remains of
dinosaurs, it would seem to me that the Indian dinos were not
significantly effected by the eruptions.

There is a lot written on the Deccan basalts, but I
can't seem to find any of my refs on the subject, but here is a
very short (and dated) reference on the subject:

McLean, D. M. 1982. Deccan volcanism and the Cretaceous-
Tertiary Transition. _IN_ D.A. Russell and G. Rice (eds.),
Cretaceous-Tertiary Extinctions and Possible Terrestrial
Extraterrestrial Causes. Syllogeus, volume 39:143-144.

I seem to remember that Sankar Chatterjee has also
written some GOOD papers on the fauna in this region.  :-)

             <pb>
--
                 Phil Bigelow
                 bh162@scn.org