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



> On "Global Warning", on the History Channel, it says that 55 million years
> ago, earth was a "fiery hell".   It was covered with massive volcanic
> activity that triggered a methane release.
>
> Last massive volcanic activity on Earth I know of was teh volcanic traps
> in
> India at the time of the end-Cretaceous extinction.
>
> What are they talking about?

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

A good review of the effect on North American mammals is Gingerich, P.D.
2006. Environment and evolution through the Paleocene?Eocene thermal
maximum. TRENDS in Ecology and Evolution 21: 246-253.


Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661

Faculty Director, Earth, Life & Time Program, College Park Scholars
http://www.geol.umd.edu/~jmerck/eltsite/
Fax: 301-405-0796

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA