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RE: Terra Nova: thoughts

> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] 
> On Behalf Of David Marjanovic
> Sent: Tuesday, September 27, 2011 5:31 PM
> To: DML
> Subject: Re: Terra Nova: thoughts
> >  I know that limestone didn't originate in teh Cretaceous, 
> unless you  
> > happen to live where it did. I don't think it's all that old  
> > everywhere on Earth. Certainly not in Texas. Evidently all  
> > pre-Cretaceous rock here is sandstone and shale. And occasional  
> > granite. Also chert, but in isolated small rocks, and 
> probably from  
> > the same source as the limestone.
> >
> >  Back in the Adirondacks, most rock was granite, gneiss, 
> quartz, and a  
> > much older and harder sort of limestone, but you had to 
> look for the  
> > limestone, it was hardly 95% of the rock.
> Over here, almost all limestone -- and there's lots of it -- 
> is Triassic, and most of the rest is Permian. However, it was 
> mostly still underwater in the Cretaceous.
> Stromatolites are limestone, and in some places they're 
> common enough to form entire formations. In short, there's 
> billion-year-old limestone out there.

Huge stretchs of the North American east were carbonate banks in the Cambrian 
and Ordovician, and again in the Silurian and
Devonian. The North  American Midwest and West has great gobs of Proterozoic 
and Paleozoic limestone.

So no carbonate shortage in the Cretaceous.

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
Fax: 301-314-9661               

Faculty Director, Science & Global Change Program, College Park Scholars
Fax: 301-314-9843

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