[meteorite-list] Wildfires and "Clovis Comat"

[Paul]

In "Holocene Start Impacts: EP Grondine: Rich Murray 2009.10.15" at
http://six.pairlist.net/pipermail/meteorite-list/2009-October/057362.html ,
Rich Murray wrote:

"I'm glad to see a new consensus rapidly evolving re widespread
Holocene Start impacts from myriad fragments of an 13 Ka BP
ice comet."

What consensus? Given that many paleoclimatologists, archaeologists,
and Quaternary geologists are having extreme problems reproducing
the results by Firestone, West, and others, it looks like the "Clovis Comet"
is turning into fiasco like the Permian-Triassic extinction claims where
Luanne Becker and scientists claimed to have found positive proof of
a Permian--Triassic extraterrestrial impact only to have it all fall apart
when other geologists, paleontologists, and paleopedologists tried to
reproduced their results and critically examined their findings. 

A good example of this is a  recent paper that discusses evidence 
related to the "Clovis Comet" hypothesis of Firestone, west, and 
others is:

Marlon, J. R., P. J. Bartlein, M. K. Walsh, S. P. Harrison, K. J. 
Brown, M. E. Edwards, P. E. Higuera, M. J. Power, R. S. Anderson,
C. Briles, A. Brunelle, C. Carcaillet, M. Daniels, F. S. Hu, M. 
Lavoiem, C. Longn, T. Minckley, P. J. H. Richard, A. C. Scott,
D. S. Shafer, W. Tinners, C. E. Umbanhowar, Jr., and C. Whitlock,
2009, Wildfire responses to abrupt climate change in North America.
Proceedinds of the National Academy of Sciences. vol. 106, no. 8,
pp. 2519-2524. doi: 10.1073/pnas.0808212106 

Abstract at:

 http://www.pnas.org/content/106/8/2519

The abstract in part states:

"We also test the hypothesis that a comet impact initiated 
continental-scale wildfires at 12.9 ka; the data do not support 
this idea, nor are continent-wide fires indicated at any time 
during deglaciation."

and

"Biomass burning gradually increased from the glacial period to
the beginning of the Younger Dryas. Although there are changes 
in biomass burning during the Younger Dryas, there is no 
systematic trend. There is a further increase in biomass burning 
after the Younger Dryas. Intervals of rapid climate change at 
13.9, 13.2, and 11.7 ka are marked by large increases in fire 
activity."

This paper concluded:

"No continent-wide fire response is observed at the beginning
 of the Younger Dryas chronozone, the time of the hypothesized 
comet impact. The results provide no evidence of synchronous 
continent-wide biomass burning at any time during the LGIT."

Note "LGIT" = last glacial–interglacial transition.

It is quite clear from this paper that the alleged "consensus" on
the "Clovis Comet" is quite imaginary. It looks like the validity
of the Clovis Comet is far from settled as there are many papers,
both pro and con, that are either in press or in preparation. 

Yours,

Paul H.