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RE: Epidexipteryx



> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] 
> On Behalf Of Matthew Martyniuk
>
> > Yes...
> >
> >> which are now radiometrically dated at 152-168 million years.
> >
> > No, no, no.
> >
> > Wang Xiaolin, Zhou Zhonghe, He Huaiyu, Jin Fan, Wang 
> Yuanqing, Zhang 
> > Jiangyong, Wang Yuan, Xu Xing & Zhang Fucheng: Stratigraphy 
> and age of 
> > the Daohugou Bed in Ningcheng, Inner Mongolia, Chinese Science 
> > Bulletin (English
> > edition) 50(20), 2369 -- 2376 (October 2005)
> >
> > The Tiaojishan Fm, which has the mentioned radiometric date ( = 
> > Middle-Late Jurassic boundary), underlies the Daohugou Bed, 
> rather than overlying it.
> >
> 
> What about...
> 
> Liu, Y., Liu, Y., and Zhang, H. (2006). "LA-ICPMS zircon U-Pb 
> dating in the Jurassic Daohugou Beds and correlative strata 
> in Ningcheng of Inner Mongolia." Acta Geologica Sinica 
> (English Edition), 80(5):
> 733-742.
> 
> ...which found a mid-Late Jurassic age?

Long story short: this is an unresolved situation, with some rather bitter
differences of opinion between different geological research units in China.
Will be nice to see it resolved.

(Basically, wickedly evil structural geology making it hard to determine if
any given bed overlies or underlies any other given bed...).

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