Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watnot!watmath!clyde!rutgers!seismo!mcvax!cernvax!ethz!srp
From: srp@ethz.UUCP
Newsgroups: sci.bio,sci.astro
Subject: Re: Mass extinctions
Message-ID: <51@ethz.UUCP>
Date: Thu, 2-Apr-87 03:37:46 EST
Article-I.D.: ethz.51
Posted: Thu Apr  2 03:37:46 1987
Date-Received: Sat, 4-Apr-87 19:00:54 EST
References: <6760@alice.uUCp> <496@uokmax.UUCP>
Reply-To: srp@ethz.UUCP (Scott Presnell)
Organization: Chem. Dept., Swiss Federal Inst. of Tech. (ETH-Zurich)
Lines: 32
Xref: utgpu sci.bio:217 sci.astro:796

In article <496@uokmax.UUCP> david@uokmax.UUCP (David Lee Cox) writes:

>I really like this discussion, but am a little confused about a couple of
>things, What would volcanoes, or meteors do that could cause mass
>extinctions?

Meteor hit's could cause a lot of debris to be thrown into the atmosphere.
If a meteor were to hit in the ocean, lots of water would vaporize.  Large
volcano eruptions could do the same thing.  Both of these events would
block sunlight, thus causing a planet wide "stall-out" of photosynthesis,
the major producer of biomass on the planet.  The food chain would break,
and a lot of organisms would "starve", from lack of biomass (food) or lack
of raw energy (light).  This is somewhat similar to the "nuclear-winter"
hypothesis.  

Some more questions...

What was the distribution of photosynthetic vs. non-photosynthetic
extinctions at the C/T boundary?

If it was a meteor strike, where did it hit? Hudson bay?

-- 
-----------

Scott Presnell  Swiss Federal Institute of Technology (ETH-Zentrum)
		Department of Organic Chemistry
		Universitaetsstrasse 16
		CH-8092 Zurich Switzerland.

uucp:		...seismo!mcvax!cernvax!ethz!srp     (srp@ethz.uucp)
earn/bitnet:	Benner@CZHETH5A