Including Original "Paul H. Letters" Copyright © 1996-2017 Paul V. Heinrich - All rights reserved.



Saturday, 28 July 2012

Younger Dryas Impact Hypothesis Discussion Heats Up Again

Younger Dryas Impact Hypothesis Discussion Heats Up Again

The discussion about the Younger Dryas Impact has
heated up again with a flurry of comments in the
Proceedings of the National Academy of Sciences of
the United States of America concerning the paper:

Israde-Alcántara, I., J. L. Bischoff, G. Domínguez-Vázquezc,
H.-C. Li, P. S. DeCarli, T. E. Bunch, J. H. Wittkef, J. C. Weaver,
R. B. Firestone, A. West, J. P. Kennett, C. Mercer, S. Xie,
E. K. Richman, C. R. Kinzie, and w. S. Wolbach, 2012,
Evidence from central Mexico supporting the Younger
Dryas extraterrestrial impact hypothesis. Proceedings
of the National Academy of Sciences of the United States
of America. vol. 109, no. 13, pp. E738-E747
http://www.pnas.org/content/109/13/E738.abstract

The replies, which can be found at
http://www.pnas.org/content/early/recent , are

1. Blaauw, M., V. T. Holliday, J. L. Gill, and K. Nicoll, 2012,
Age models and the Younger Dryas Impact Hypothesis.
PNAS 2012 ; published ahead of print July 24, 2012.

2. Boslough, M., 2012, Inconsistent impact hypotheses
for the Younger Dryas. PNAS 2012 ; published ahead of
print July 24, 2012.

3. Daulton, T. L., 2012, Suspect cubic diamond “impact”
proxy and a suspect lonsdaleite identification. PNAS 2012 ;
published ahead of print July 24, 2012.

4. Gill, J. L. J. L. Blois, S. Goring, J. R. Marlon, P. J. Bartlein,
K. Nicoll, A. C. Scott, and C. Whitlock, 2012, Paleoecological
changes at Lake Cuitzeo were not consistent with an
extraterrestrial impact. PNAS 2012 ; published ahead of
print July 24, 2012.

and 5. Hardiman, M., A. C. Scott, M. E. Collinson, and R. S.
Anderson, 2012, Inconsistent redefining of the carbon
spherule “impact” proxy. PNAS 2012 ; published ahead
of print July 24, 2012.

The reply to the above comments, which is also at
http://www.pnas.org/content/early/recent , is:

Israde-Alcantara, I., J. L. Bischoff, P. S. DeCarli, G.
Domínguez-Vázquez, T. E. Bunch, R. B. Firestone,
J. P. Kennett, and A. West, 2012, Reply to Blaauw et al.,
Boslough, Daulton, Gill et al., and Hardiman et al.:
Younger Dryas impact proxies in Lake Cuitzeo,
Mexico. PNAS 2012 ; published ahead of print July
24, 2012.

A related paper is:

van Hoesel, A., W. Z. Hoek, F. Braadbaart, J. van der Plicht, G. M.
Pennocka, andM. R. Drurya, 2012, Nanodiamonds and wildfire
evidence in the Usselo horizon postdate the Allerød-Younger
Dryas boundary. Proceedings of the National Academy of
Sciences of the United States of America. vol. 109, no. 20,
pp. 7648-7653.
http://www.pnas.org/content/109/20/7648.abstract

Best wishes,

Paul H.