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RE: Why non-avian dinosaurs weren't able to survive

> From: Denver Fowler [mailto:df9465@yahoo.co.uk]
> Sent: Tuesday, November 24, 2015 10:56 AM
> To: tholtz@umd.edu; ruben@mrbrklyn.com; frank@blissnet.com; dinosaur@usc.edu
> Subject: Re: Why non-avian dinosaurs weren't able to survive
> >> Additionally, there was a great physical destruction.  Not much 
> >> sediment.>Exactly: you only get fossils in a depositional
> environment. The effects of the Chicxulub impact didn't increase rates of 
> sedimentation (well, except for tsunami deposits along the
> Gulf...), so you don't get any more chance of fossilization than other times.
> >
> >Terrestrial deposition is very episodic and spotty: it isn't like deep sea 
> >or lake sedimentation. You only get overbank deposits when
> the river floods; you only get channel deposits when the channel is RIGHT at 
> that spot, etc.
> The uppermost Hell Creek (towards the K-Pg) is actually a period of high 
> accommodation and significant deposition. The reason why
> the iridium layer & various ashes are preserved at the K-Pg (and a few metres 
> above and below) is because there is deposition
> occurring. There is little evidence for any significant hiatus through the 
> K-Pg in the Hell Creek.
High for a terrestrial deposit, yes. But as a once-paleoceanographer (not 
entirely be choice...) I can tell you that with the exception of lakes, no 
terrestrial form of deposition shows the kind of nearly-continuous 
sedimentation you have in some marine environments.

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu         Phone: 301-405-4084
Senior Lecturer, Vertebrate Paleontology
Office: Geology 4106, 8000 Regents Dr., College Park MD 20742
Dept. of Geology, University of Maryland
Phone: 301-405-6965
Fax: 301-314-9661              

Faculty Director, Science & Global Change Program, College Park Scholars
Office: Centreville 1216, 4243 Valley Dr., College Park MD 20742
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        8000 Regents Drive
                        University of Maryland
                        College Park, MD 20742-4211 USA