On Fri, Jun 16th, 2017 at 9:51 PM, Thomas Richard Holtz <firstname.lastname@example.org> wrote:
> Yes, the 180 km is probably the most accurate, and current dating for the
> boundary is 66 Ma. Those who still use 65.5 or 65 have not kept up with the
> new dating techniques and results.
The date given by Renne et all in 2013 seems to have a surprisingly small standard deviation;
66.043 +/- 0.011 MYA. That would seem to narrow it down to within a 44,000 year time span
(at two standard deviations). Is Argon-Argon dating really that precise?
I worked as an archaeologist for many years, and I was used to seeing much larger standard
deviations on much more recent dates (C14, thermoluminescence, Uranium-Thorium, etc).
Admittedly that was around the turn of the century, so technology may have (in fact, most
likely *has*) advanced somewhat since then. :-)
Thomas R. Holtz, Jr.
Email: email@example.com Phone: 301-405-4084
Principal Lecturer, Vertebrate Paleontology
Office: Geology 4106, 8000 Regents Dr., College Park MD 20742
Dept. of Geology, University of Maryland
Faculty Director, Science & Global Change Program, College Park Scholars
Office: Centreville 1216, 4243 Valley Dr., College Park MD 20742
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