[meteorite-list] On the possibility of a late pleistocene extraterrestrial impact: LA-ICP-MS analysis of the black mat and Usselo Horizon samples, AV Andronikov, DS Lauretta, IE Andronikova, RJ Maxwell 2011: Rich Murray 2011.12.30

From: Rich Murray <rmforall_at_meteoritecentral.com>
Date: Fri, 30 Dec 2011 18:53:32 -0800
Message-ID: <CAHqJ8pY60E4VuHRO6b8_ZOP_zpusV2f6JSdTY4rB=avfn8hzHw_at_mail.gmail.com>

On the possibility of a late pleistocene extraterrestrial impact:
LA-ICP-MS analysis of the black mat and Usselo Horizon samples, AV
Andronikov, DS Lauretta, IE Andronikova, RJ Maxwell 2011: Rich Murray
2011.12.30


http://cosmictusk.com/game-changer-independent-confirmation-of-elevated-et-materials-in-arizona-and-dutch-black-mats

http://www.scribd.com/doc/76731890/ON-THE-POSSIBILITY-OF-A-LATE-PLEISTOCENE-EXTRATERRESTRIAL-IMPACT-LA-ICP-MS-ANALYSIS-OF-THE-BLACK-MAT-AND-USSELO-HORIZON-SAMPLES-Andronikov-et-al-20

74th Annual Meteoritical Society Meeting (2011) 5008.pdf

On the possibility of a late pleistocene extraterrestrial impact:
LA-ICP-MS analysis of the black mat and Usselo Horizon samples.
A. V. Andronikov,
D. S. Lauretta,
I. E. Andronikova,
R. J. Maxwell.
Department of Planetary Sciences,
Lunar and Planetary Laboratory,
University of Arizona,
Tucson, AZ, 85721 USA
E-mail: andron at lpl.arizona.edu

Introduction:

A dark layer of organic-rich material contemporaneous with the onset
of the Younger Dryas (YD) cooling(12.9 ka) has been identified in
North America (black mat; BM) and Western Europe (Usselo Horizon; UH).

The following main hypotheses on the origin of this layer exist:

a) it formed by water-transported organic material;

b) it is the result of a heavy deposition of algae in a shallow
fresh-water reservoir;

c) it formed in response to periods of spring-fed stream activation
when ground water oxidized organic material;

d) it resulted from wood fires and decomposition of charred wood;

or e) it resulted from the impact of a comet or asteroid [1,2].

Most BM sequences contain a thin (2-5 cm) basal pitch-black layer
likely corresponding to the lower YD boundary (LYDB).

The UH sequences are represented by dark charcoal-rich layers within
aeolian sands [3].

Discussion:

Trace element concentrations in the BM (Arizona) and UH (Holland and
France) samples were studied using LA-ICP-MS.

Trace element compositions of the LYDB layers which directly underlie
the BM, and the BM itself are different:
the BM displays trace element concentrations similar to the average
continental crust,
while the LYDB layers are strongly enriched in REE (up to 800xCI chondrite)
and relatively depleted in Ta, Nb, Zr, and Hf (down to 30xCI).

Such a difference in compositions can point to a sharp change in the
conditions of sedimentation just before LYDB layer deposition.

LYDB, BM and UH samples display 2-5 times higher concentrations of
PGEs than the sediments underlying BM sequences.

Additionally, LYDB samples display a positive correlation between Ni
and Ir accompanied by an Os-to-Ir ratio of 1:1
and overall higher concentrations of both Os and Ir.

In contrast, UH samples do not display any correlation between Os and Ir,
and BM samples have an Os-to-Ir ratio of 1:2, which is more typical
for terrestrial sediments [4].

Overall, UH samples display trace element characteristics that are a
mixture between those typical of the BM and the LYDB.

Trace element distributions and relations for samples of LYDB may be
consistent with incorporation of the material of ET origin and could,
therefore, support the hypothesis that an impact occurred shortly
before the beginning of the YD cooling 12.9 ka.

References:

[1] Firestone R.B. et al. 2007.
Proceedings of the National Academy of Science
104:16016-16021.

[2] Haynes C.V. et al. 2010.
Proceedings of the National Academy of Science
107:4010-4015.

[3] Kaiser K. et al. 2009.
Boreas
38:591-609

[4] Agiorgitis G.and Wolf R. 1984.
Chemical Geology
42:277-286.


http://cosmictusk.com/field-report-andronikov-expedition-to-examine-black-mat

http://www.scribd.com/doc/76814554/Black-Mat-Andronikov-2011-Lower-Younger-Dryas-Boundary-Europe-Report
24 pages with color photos

A report on the field trip to Belgium, the Netherlands and Russia (May
1 to 31, 2011)
(A. Andronikov)

via www.CosmicTusk.com blog
"George Howard" <george at restorationsystems.com>


10 m broken rock hill with black glazes, W of Rancho Alegre Road, S of
Coyote Trail, W of Hwy 14, S of Santa Fe, New Mexico, tour of 50
photos 1 MB size each via DropBox: Rich Murray 2011.07.28 2011.08.03
http://rmforall.blogspot.com/2011/08/10-m-broken-rock-hill-with-black-glazes.html
http://rmforall.blogspot.com/2011/08/35479730-106085926-1865-km-el-top-10-m.html
photos 3-5 of 50
http://tech.groups.yahoo.com/group/astrodeep/message/92

Rich Murray
254-A Donax Avenue
Imperial Beach, CA 91932
rmforall at gmail.com
505-819-7388
rich.murray11 Skype audio, video
Received on Fri 30 Dec 2011 09:53:32 PM PST