[meteorite-list] New PNAS Paper About Firestone’s Impact Hypothesis

From: Paul <bristolia_at_meteoritecentral.com>
Date: Wed, 13 Aug 2008 09:44:12 -0700 (PDT)
Message-ID: <972799.97711.qm_at_web36202.mail.mud.yahoo.com>

The paper is:

Buchanan, B., M. Collard, and K. Edinborough, 2008,
Paleoindian demography and the extraterrestrial impact
hypothesis. Proceedings of the National Academy of
Sciences. Published online before print August 12,
2008, doi: 10.1073/pnas.0803762105

The abstract is at

http://www.pnas.org/content/early/2008/08/11/0803762105.abstract

Jaconson et al. (1987) did a study of the rate at which the
vegetation of North America changed during the last 15,000
years. They found from the examination of sevreal well-dated
and continuous paleovegetational records that there were
only three major periods of rapid vegetational change in the
northeast Midwest and southeast United States during this
time. None of them correspond to the time of Firestone?s
hypothesized impact. There is a complete lack of any
evidence of significant vegetation changes in the
paleovegetation records from numerous lake cores for
Firestone?s hypothesized impacts. These times are shown
as green lines in Figure 4 at:

http://www.hallofmaat.com/images/004Fig.jpg

Given the claims made for the size, magnitude, and
devastation of his hypothesize impact, the complete lack of
any significant effect, which can be seen the paleovegetational
records in cores from any of numerous lakes within the
Midwestern and eastern North America, as summarized
by Jaconson et al. (1987), raises the same questions about
Firestone?s hypothesis that the analysis of radiocarbon
dates by Buchanan et al. (2008) does.

References cited:

Jacobson, George L., Jr., Webb, Thompson, III, and Grimm,
Eric E., 1987, Patterns and rates of vegetational change
during the deglaciation of North America. in W. F. Ruddiman
and H. E. Wright, Jr., eds., pp. 277-287. North America
Adjacent Oceans During the Last Deglaciation. The Geology
of North America. vol. K-3. Geological Society of America,
Boulder, Colorado.
Yours,

Paul H.


      
Received on Wed 13 Aug 2008 12:44:12 PM PDT