RE: Geological timescale

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Phil Bigelow
>
> That's an important revision for Boundary researchers.  Gradstein et al.
> (1995) quote 65.00+/- 0.04 Ma for the K-T Boundary.
>
> K-T boundary rock samples were considered "good" (stratigraphically
> accurate) back in 1995.  So are these revisions the result of better
> sampling or of better instrumentation or of revisions to the calculations
> (or of all three)?

A condensation of the forthcoming Geologic Timescale 2004 can be found here:
http://www.stratigraphy.org/scale04.pdf

The details for all the new dates will be in that 500+ pp. volume: obviously
a little bitty preview in Nature does NOT cover these!!

As you can see from the abstract, the revisions are by Gradstein's team
itself!!

Something covered in the Nature news item but not in the above abstract is
that they seemed to have settled on a nomenclature for the Periods of the
various Proterozoic Eras: something for next year's class of Historical
Geology students to learn...

                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