[meteorite-list] PDF File of Scott et al. (in press) Fungus, Not comet or Catastrophe Paper Now Online

From: Rich Murray <rmforall_at_meteoritecentral.com>
Date: Mon, 21 Jun 2010 00:15:14 -0600
Message-ID: <FC0FDBD272154D62B7CD36521636FA81_at_ownerPC>

Access to the full papers balances the debate:

http://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1025&context=ssci_fac
16 pages, 2008 free full text

Wildfire and Abrupt Ecosystem Disruption on California's Northern Channel
Islands at the Allerod-Younger Dryas Boundary (13.0-12.9 ka)
Douglas J. Kennett, University of Oregon
James P. Kennett, University of California - Santa Barbara
G. J. West, University of California - Davis
Jon M. Erlandson, University of Oregon
J. R. Johnson, Santa Barbara Museum of Natural History
I. L. Hendy, University of Michigan - Ann Arbor
A. West, GeoScience Consulting
B. J. Culleton, University of Oregon
Terry L. Jones, California Polytechnic State University - San Luis Obispo
Thomas W. Stafford, Jr., Stafford Research Laboratories, Inc.
Recommended Citation
Postprint version. Published in Quaternary Science Reviews, Volume 27, Issue
27-28, December 1, 2008, pages 2530-2545. Copyright ? 2008 Elsevier Ltd. All
rights reserved. The definitive version is available at
http://dx.doi.org/10.1016/j.quascirev.2008.09.006
Abstract
Sedimentary records from California's Northern Channel Islands and the
adjacent Santa Barbara Basin (SBB) indicate intense regional biomass burning
(wildfire) at the ?ller?d?Younger Dryas boundary (~13.0?12.9 ka)
(All age ranges in this paper are expressed in thousands of calendar years
before present [ka].
Radiocarbon ages will be identified and clearly marked ?14C years?.).
Multiproxy records in SBB Ocean Drilling Project (ODP) Site 893 indicate
that these wildfires coincided with the onset of regional cooling and an
abrupt vegetational shift from closed montane forest to more open habitats.
Abrupt ecosystem disruption is evident on the Northern Channel Islands at
the ?ller?d?Younger Dryas boundary with the onset of biomass burning and
resulting mass sediment wasting of the landscape.
These wildfires coincide with the extinction of Mammuthus exilis [pygmy
mammoth].
The earliest evidence for human presence on these islands at 13.1?12.9 ka
(~11,000?10,900 14C years) is followed by an apparent 600?800 year gap in
the archaeological record, which is followed by indications of a
larger-scale colonization after 12.2 ka.
Although a number of processes could have contributed to a post 18 ka
decline in M. exilis populations (e.g., reduction of habitat due to
sea-level rise and human exploitation of limited insular populations), we
argue that the ultimate demise of M. exilis was more likely a result of
continental scale ecosystem disruption that registered across North America
at the onset of the Younger Dryas cooling episode, contemporaneous with the
extinction of other megafaunal taxa.
Evidence for ecosystem disruption at 13?12.9 ka on these offshore islands is
consistent with the Younger Dryas boundary cosmic impact hypothesis

[ Firestone, R.B., West, A., Kennett, J.P., Becker, L., Bunch, T.E., Revay,
Z.S., Schultz, P.H., Belgya, T., Kennett, D.J., Erlandson, J.M., Dickenson,
O.J., Goodyear, A.A., Harris, R.S., Howard, G.A., Kloosterman, J.B.,
Lechler, P., Mayewski, P.A., Montgomery, J., Poreda, R., Darrah, T., Que
Hee, S.S., Smith, A.R., Stich, A., Topping, W., Wittke, J.H. Wolbach, W.S.,
2007.
 Evidence for an extraterrestrial impact 12,900 years ago that contributed
to the megafaunal extinctions and Younger Dryas cooling.
Proceedings of the National Academy of Sciences 104, 16016?16021. ].
URL: http://digitalcommons.calpoly.edu/ssci_fac/24



Scott et al. Carbonaceous spherules 13

Figure 1. The Northern Channel Islands (NCI) of California, showing portions
of the
three main sections sampled, dated, and described in this paper.

[ color photos of level strata of steep canyon cliffs -- does anyone have
the coordinates?

Google Earth shows interesting topography -- any evidence for vertical
ablation via high temperature, high pressure airburst plasma? ]

(A) Verde Canyon section on Santa Rosa Island.

 (B) Sauces (a.k.a. Willows) Canyon on Santa Cruz Island.

(C) Middle Arlington Canyon on Santa Rosa Island.

Also shown on each panel (red circle) is the approximate position of the
12,900 cal BP age horizon.

Figure 2. Forms of modern and fossil carbonaceous spherules.

[ If the comparison photos had the same scale, that would help. ]

A-C. SEMs of carbonaceous spherules and elongates from a Younger Dryas black
horizon, Arlington Canyon, Santa Rosa Island, California, from Kennett et
al. (2009b).

A. Whole spherule.
B. Internal structure of outer part of spherule.
C. Internal structure of ?elongate? specimen.

D.-F. Carbonaceous spherule (cf Cenococcum, Fig 2G) from charcoal assemblage
after low intensity wildfire, Thursley, Surrey, 2006.
D. Light photograph of whole spherule.
E. SEM of outer part of broken spherule showing rind.
F. SEM of inner part of broken spherule.
G. Scanning Electron Micrograph of broken fungal sclerotium of Cenococcum
geophilium showing rind, Alberta Canada.
H.-J. Fungal sclerotium of Sclerotium rolfsii.
H. Light photograph of whole slerotium charred at 350 deg C for 5 mins.
I. SEM of broken sclerotium showing thick rind.
J. SEM of mesh-like internal structure comprising fused fungal hyphae.

K. SEM of broken ?elongate? from Arlington Canyon, illustrated by Kennett et
al.
(2009b).
Specimen shows thick outer rind and vesiculate interior.
L. SEM of internal structure of charcoalified sclerotium charred at 450 deg
C for 5 min.
Note thick rind and more vesicular interior.

Scott et al. Carbonaceous spherules 14

M-N. SRXTM digital sections of sclerotium charred at 350 deg C for 5 min
showing different appearance depending on the plane of section.

O. TEM of carbonaceous fragment from a powdered spherule interpreted as
showing ?nanodiamonds? from Kennett et al. (2009b).
P. TEM of fragment interpreted as lonsdailite crystal from Kennett et al.
(2009b).

Q,R. TEM of thin sections through charred fungal sclerotium hyphal wall.
Q. dark areas similar to those shown in 2O.
R. Organised area similar to that shown in 2P.

[ see also:

http://repository.library.csuci.edu/jspui/bitstream/10139/782/5/Orr_Geochronology_Santa_Rosa_Island~.pdf
5 pages, 1967
GEOCHRONOLOGY OF SANTA ROSA ISLAND, CALIFORNIA
Phil C. Orr
Santa Barbara Museum of Natural History ]

In mutual service, Rich Murray


----- Original Message -----
From: "Paul H." <oxytropidoceras at cox.net>
To: <meteorite-list at meteoritecentral.com>
Sent: Sunday, June 20, 2010 12:09 AM
Subject: [meteorite-list] PDF File of Scott et al. (in press) Fungus, Not
comet or Catastrophe Paper Now Online


 Scott, A. C., N. Pinter, M. E. Collinson, M. Hardiman,
S. Anderson, A. P. R. Brain, S. Y. Smith, F. Marone,
and M. Stampanoni, in press, Fungus, not comet or
catastrophe, accounts for carbonaceous spherules in
the Younger Dryas "impact layer". Geophysical Research
Letters doi:10.1029/2010GL043345, in press

can be downloaded for free from

 http://sciences.blogs.liberation.fr/files/youg-dryas-sans-impact.pdf

 It is part of a web page, "Les mammouths n'ont pas ?t?
 tu?s par une com?te" at

 http://sciences.blogs.liberation.fr/home/2010/06/les-mamouths-nont-pas-%C3%A9t%C3%A9-tu%C3%A9s-par-une-com%C3%A8te.html Yours, Paul H.______________________________________________Visit the Archives athttp://www.meteoritecentral.com/mailing-list-archives.htmlMeteorite-list mailing listMeteorite-list at meteoritecentral.comhttp://six.pairlist.net/mailman/listinfo/meteorite-list
Received on Mon 21 Jun 2010 02:15:14 AM PDT