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Re: end-of-cretaceous climate



According to a recent episode of The Universe, the likely impact candidate is one of the Batista Impact Family from the asteroid belt. The family is composed of about 130,000 objects. The family was formed 160 million years ago as a result of the impact of two large bodies in the belt, one of them being the "size of Mount Everest". Estimates are that 20% of the Batista family had trajectories and energy sufficient to escape the belt and 2% had the potential to impact the Earth. If all this is to be believed, then it took about 100 million years for one of these escaped family members to cross paths with the Earth. So dinosaurs (except for the Aves) were doomed well before the end of the Cretaceous.

However, this was a television program.

Dan


Thomas R. Holtz, Jr. wrote:
From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] On Behalf Of hammeris1@bellsouth.net

From my (admittedly amateur) reading, it would seem that South America had the healthiest climate right before the 'end' in terms of volcanism and dino population.

Dino population? We have no idea. At present we don't have latest
Maastrichtian South American dinosaurs identified.


Volcanism? The Andes are going through eruptions then, but they have been a
long-lived constant background igneous arc in the late Mesozoic and
Cenozoic, not like the burst of the Deccan Traps or the Cordilleran system
in North America, with its shifting orogenic styles.

But it is not like Europe was going through lots of volcanism at the time,
nor much of northern & central Asia.

Is this accurate, or was Africa or some other continent healthier in dino-strength

Very few parts of the world have good statistical samples of dinosaur fossils from the last couple of million years of the Cretaceous. Would LOVE to know what is going on, but without fossils we can't.

right before the big smackdown from the Kuiper belt?

Why the Kuiper Belt? None of the recent work points towards a cometary impact, but instead more likely a carbonaceous chondrite.

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