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Re: Why was Earth a fiery hell 55 million years ago?



I bought and saved in PDF format a copy of the article,

     Science 27 April 2007:
     Vol. 316. no. 5824, p. 527
     DOI: 10.1126/science.316.5824.527


News of the Week GEOCHEMISTRY: Humongous Eruptions Linked to Dramatic Environmental Changes Richard A. Kerr

if anyone wants it.

It discusses in brief detail work to determine basalt flood eruptions in the northern Atlantic and the Caribbean at 55 million years ago at the time of the global warming, and it's the most detail I found so far. They thought that the timing of the Caribbean eruption works out better, but there wasn't enough detail on either (except for the issue of timing itself), and it begins to sound rather like trying to figure out which of two likely factors that occurred close together in time really caused the end Cretaceous extinction. One begins to see why they'd be saying vague things like "Earth at the time was covered in volcanoes", and "Earth's climate was already on the brink when the (second set of volcanoes) happened". Well, now, it sounds as if the North Atlantic was covered in volcanoes.. .

The idea that basalt flood eruptions would cause such a thing makes sense. I just thought that there were only two such things in history.

Yours,
Dora Smith
Austin, TX
tiggernut24@yahoo.com

----- Original Message ----- From: <tholtz@geol.umd.edu>
To: <villandra@austin.rr.com>
Cc: <dinosaur@usc.edu>
Sent: Saturday, January 26, 2008 7:45 AM
Subject: Re: Why was Earth a fiery hell 55 million years ago?

They are talking about the Paleocene-Eocene Thermal Maximums (PETM), a massive but very short term spike in temperature triggered by a massive release of greenhouse gasses (most likely marine methane) triggered by... Um... Okay, there is not yet a strong candidate for the actual trigger: some prefer an impactor, others for terrestrial causes.

A brief wiki-review is at http://en.wikipedia.org/wiki/PETM




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