From: Rich Blinne (richblinne@hotmail.com)
Date: Mon Sep 09 2002 - 19:15:10 EDT
While we are on the subject of dating the following article is in the 6
September Science. Note the last sentence of the abstract confirming dating
by other than Pb/Pb isochrons. Since the dating source is extraterrestrial
I wonder how the YEC are going to come up with a contamination theory.
Lead Isotopic Ages of Chondrules and Calcium-Aluminum-Rich Inclusions
Yuri Amelin,1*dagger Alexander N. Krot,2 Ian D. Hutcheon,3 Alexander A.
Ulyanov4
The lead-lead isochron age of chondrules in the CR chondrite Acfer 059 is
4564.7 ± 0.6 million years ago (Ma), whereas the lead isotopic age of
calcium-aluminum-rich inclusions (CAIs) in the CV chondrite Efremovka is
4567.2 ± 0.6 Ma. This gives an interval of 2.5 ± 1.2 million years (My)
between formation of the CV CAIs and the CR chondrules and indicates that
CAI- and chondrule-forming events lasted for at least 1.3 My. This time
interval is consistent with a 2- to 3-My age difference between CR CAIs and
chondrules inferred from the differences in their initial 26Al/27Al ratios
and supports the chronological significance of the 26Al-26Mg systematics.
1 Department of Earth Sciences, Royal Ontario Museum, Toronto, ON M5S 2C6,
Canada.
2 Hawaii Institute of Geophysics and Planetology, School of Ocean and Earth
Science and Technology, University of Hawaii, Honolulu, HI 96822, USA.
3 Lawrence Livermore National Laboratory, Livermore, CA 94451, USA.
4 M. V. Lomonosov Moscow State University, Moscow 117999, Russia.
* Present address: Geological Survey of Canada, 601 Booth Street, Ottawa,
ON K1A 0E8, Canada.
dagger To whom correspondence should be addressed. E-mail:
yamelin@NRCan.gc.ca
Volume 297, Number 5587, Issue of 6 Sep 2002, pp. 1678-1683.
_________________________________________________________________
Join the worldís largest e-mail service with MSN Hotmail.
http://www.hotmail.com
This archive was generated by hypermail 2.1.4 : Tue Sep 10 2002 - 00:46:11 EDT