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Re: Volcanoes (comments on pterosaur extinction)




Tommy, Emma, et al.,
Thanks for setting me straight on the Deccan traps (I obviously need to read up on them before wildly speculating).
But this just strengthens my belief that they had very little (if anything) to do with the worldwide extinction of dinosaurs (non-avian) or of any other major taxa that were wiped out at the time. The Deccan eruptions must have polluted the atmosphere something awful at times, but I think that must have been a minor nuisance compared to the bolide collision. Of course, I might change my mind after reading the new Sarjeant and Currie paper (but I doubt it).
--------Ken
*******************************************************
From: Tyrberg Tommy <tommy.tyrberg@aerotechtelub.se>
Reply-To: tommy.tyrberg@aerotechtelub.se
To: "'dinosaur@usc.edu'" <dinosaur@usc.edu>
Subject: Re: Volcanoes (comments on pterosaur extinction)
Date: Thu, 8 Feb 2001 12:40:07 +0100

It does not make sense. The inter-trappan beds together with dinosaurs and
dinosaur eggs contain well-developed soil profiles which must have taken at
least centuries, more likely millenia to develop. In any case one would
hardly expect herbivorous dinosaurs to inhabit freshly erupted lava fields
until a reasoable vegetation cover had evolved, again a matter of centuries,
even in a tropical climate.
The intertrappan beds show that the Deccan eruptions were at least not
initially fatal to dinosaurs even on the isolated indian island, much less
worldwide, though a later more intense phase may theoretically have been so.
It is very unfortunate that we do not have any Palaeocene faunas from India,
before it contacted Laurasia, so we have no idea what vertebrates, if any,
survived there.
Tommy Tyrberg


>Since I'm not a geologist, I don't know if this will make sense, but what
about the following scenario:
>1. Bolide crashes into the Earth.
>2. Deccan traps triggered to erupt.
>3. Iridium (etc.) rains down on top of these initial lava beds during the
following weeks and months (years??).
>4. Iridium layer is then covered by subsequent eruptions, and thus
sandwiched between layers of lava.

>Is such a scenario possible (and if so, very probable)? I suppose someone
has proposed such a scenario, but I'm not sure what the arguments might be
against it. >>
>Cheers, Ken


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