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RE: Tsagantsabian age

From: "Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>
To: <msdonovan66@hotmail.com>
Subject: RE: the last stegosaur
Date: Tue, 30 Jul 2002 08:45:22 -0400

> >In answer to your question, though, Wuerhosaurus was once
> considered to be
> >the latest-occuring stegosaur, but new (as you note) new data
> indicate that
> >it could be older than the Wealden stegosaur material.
> What new data? Shuvalov wrote that Tsagantsabian sediments had already
> begun to accumulate by the end of the late Jurassic, which
> suggests an early
> EK age for Wuerhosaurus. Does other new data confirm this?

The Shuvalov work IS the new data (compared to older work).

I notice there are at least two units of EK age underlying the Lianmuqin-presumably the basis for the old estimate of a late EK age for Wuerhosaurus. Shuvalov showed that Tsagantsabian datable materials from Mongolia have yielded ages of about 130 Ma, so maybe Wuerhosaurus, from the correlative Lianmuqin, was neither very early nor late in the EK but of c Hauterivian age. I don't know if that's older than the Wealden- probably coeval.

Thomas R. Holtz, Jr. Vertebrate Paleontologist Department of Geology Director, Earth, Life & Time Program University of Maryland College Park Scholars College Park, MD 20742 http://www.geol.umd.edu/~tholtz/tholtz.htm http://www.geol.umd.edu/~jmerck/eltsite Phone: 301-405-4084 Email: tholtz@geol.umd.edu Fax (Geol): 301-314-9661 Fax (CPS-ELT): 301-405-0796

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