[meteorite-list] 3 reports re NW Venezuela Andes black mat at 12.9 Ka, WC Mahaney et al, 2009-2011, free full texts: CosmicTusk.com: Rich Murray 2011.04.29

From: Rich Murray <rmforall_at_meteoritecentral.com>
Date: Thu, 28 Apr 2011 23:07:33 -0700
Message-ID: <BANLkTin9CfcqV4SRcqhq0e0tvnGU3dH==w_at_mail.gmail.com>

3 reports re NW Venezuela Andes black mat at 12.9 Ka, WC Mahaney et
al, 2009-2011, free full texts: CosmicTusk.com: Rich Murray 2011.04.29
http://rmforall.blogspot.com/2011_04_01_archive.htm
Friday, April 29, 2011
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http://www.scribd.com/doc/54163707/Evidence-from-the-northwestern-Venezuelan-Andes-for-extraterrestrial-impact-The-black-mat-enigma

Geomorphology 116 (2010) 48?57

Evidence from the northwestern Venezuelan Andes for extraterrestrial
impact: The black mat enigma

W.C. Mahaney a,?, V. Kalm b, D.H. Krinsley c, P. Tricart d, S.
Schwartz d, J. Dohm e,f, K.J. Kim g, B. Kapran a,
M.W. Milner a, R. Beukens h, S. Boccia i, R.G.V. Hancock j, K.M. Hart
k, B. Kelleher k

a Quaternary Surveys, 26 Thornhill Ave., Thornhill, Ontario, Canada L4J 1J4
b Institute of Ecology & Earth Sciences, Tartu University, Tartu,
EE51014, Estonia
c Institute of Geological Sciences, University of Oregon, Eugene,
Oregon, 97403-1272, USA
d Laboratoire de Geodynamique des Cha?nes Alpines, University of
Grenoble, Observatoire des Sciences de l'Univers, 38041, Grenoble,
France
e Department of Hydrology and Water Resources, University of Arizona,
Tucson, Az., 85721, USA
f The Museum, The University of Tokyo, Tokyo, 113-0033, Japan
g Geological Research Division (Prospective Geoscience Research
Department), Korea Institute of Geoscience and Mineral Resources
(KIGAM), 92 Gwahang-no, Yuseong-gu, Daejeon 305-350, Republic of Korea
h IsoTrace Lab, Dept of Physics, University of Toronto, Toronto,
Ontario, Canada M5S 1A7
i Department of Materials Science, University of Toronto, Toronto,
Ontario, Canada M5S 3E4
j Department of Medical Physics and Applied Radiation Sciences and
Department of Anthropology, McMaster University, Hamilton, Ontario,
Canada L8S 4K1
k School of Chemical Sciences, Dublin City University, Ballymun Road,
Glasnevin, Dublin 9, Ireland

a r t i c l e i n f o a b s t r a c t
Article history:
Received 11 January 2009
Received in revised form 9 October 2009
Accepted 14 October 2009
Available online 24 October 2009
Keywords:
Asteroid impact
Black mat
Younger Dryas
Paleoclimate

A carbon-rich black layer encrusted on a sandy pebbly bed of outwash
in the northern Venezuelan Andes, previously considered the result of
an alpine grass fire, is now recognized as a ?black mat? candidate
correlative with ClovisAge sites inNorth America, falling within the
range of ?blackmat? dated sites (~12.9 ka cal BP).
As such, the bed at site MUM7B, which dates to <11.8 ka 14C years BP
(raw dates) and appears to be contemporaneous with the Younger Dryas
(YD) cooling event, marks a possibly much more extensive occurrence
than previously identified.
No fossils (megafauna) or tool assemblages were observed at this newly
identified candidate site (3800 a.m.s.l.), as in the case of the North
American sites.
Here, evidence is presented for an extraterrestrial impact event at
~12.9 ka. The impact-related Andean bed, located ~20 cmabove 13.7-13.3
ka cal BP alluvial and glaciolacustrine deposits, falls within the
sediment characteristics and age range of ?black mat? dated sites
(~12.9 ka cal BP) in North America.
Site sediment characteristics include: carbon, glassy spherules,
magnetic microspherules, carbon mat ?welded? onto coarse granular
material, occasional presence of platinum group metals (Rh and Ru),
planar deformation features (pdfs) in fine silt-size fragmental grains
of quartz, as well as
orthoclase, and monazite (with an abundance of Rare Earth Elements -- REEs).
If the candidate site is ?black mat?, correlative with the ?black mat?
sites of North America, such an extensive occurrence may support the
hypothesized airburst/impact over the Laurentide Glacier, which led to
a reversal of Aller?d warming and the onset of YD cooling and
readvance of glaciers.
While this finding does not confirm such, it merits further
investigation,which includes the reconnaissance for additional sites
in South America. Furthermore, if confirmed, such an extensive
occurrence may corroborate an impact origin.
? 2009 Elsevier B.V. All rights reserved.



http://www.scribd.com/doc/54163938/Evidence-for-a-cosmogenic-origin-of-fired-glaciofluvial-beds-in-the-northwestern-Andes-Correlation-with-experimentally-heated-quartz-and-feldspar

Sedimentary Geology 231 (2010) 31-40

Evidence for a cosmogenic origin of fired glaciofluvial beds in the
northwestern Andes: Correlation with experimentally heated quartz and
feldspar

William C. Mahaney a,?, David Krinsley b, Volli Kalm c

a Quaternary Surveys, 26 Thornhill Ave., Thornhill, Ontario, Canada L4J 1JS4
b Department of Geological Sciences, University of Oregon, Eugene, OR,
USA 97403-1272
c Institute of Ecology and Earth Sciences, Tartu University, Tartu,
Estonia 50411

a r t i c l e i n f o a b s t r a c t
Article history:
Received 12 June 2010
Received in revised form 3 August 2010
Accepted 19 August 2010
Available online 26 August 2010
Editor: M.R. Bennett
Keywords:
Younger Dryas
Laurentide Glacier airburst
Black Mat
Fired rock

Fired sediment, considered equivalent to the ?Black Mat? impact of
12.9 ka, has been located and analyzed in the Andes of northwestern
Venezuela. The ?Black Mat? refers to possible fallout from the Encke
Comet airburst presumed to have occurred over the Laurentide Ice
Sheet, the impact spreading ejecta over large portions of North
America and Europe, making it an interhemispheric event of
considerable magnitude.
These possible equivalent beds in the northern Andes, first considered
to result from a lightning-induced conflagration adjacent to the
retreating Late Wisconsinan (M?rida Glaciation) ice, are now known to
have undergone intense heating upon impact to a temperature much
higher than what would occur in a wet, first-stage, successional
tundra.
Analyses carried out by SEM and FESEM, in SE and BSE modes, show
massive microdisruption on grain surfaces, fractures diminishing with
depth toward grain interiors and C welded onto quartz and plagioclase
minerals.
Bubbles on some grains, possibly the result of exclusion of
water-ofcrystallization, are seen on some samples, principally quartz.
The presence of copious monazite in the carbonaceous coatings is
considered part of the incoming ejecta, as it is not a common
indicator mineral in
the local lithology.
Analysis by SEM and FESEM of quartz and plagioclase subjected
experimentally to temperatures ranging from 500 to 900 ?C shows that
intense heating affects resident mineralogies to differing extents,
with grain disruption more prevalent along cleavage planes deep into
grain interiors.
The intergrowth of carbonaceous ?black mat? material with thermally
disrupted and fragmented quartz and feldspar, a ?welded? patina of
100?400 nm thickness could only occur with temperatures in excess of
900 ?C, the event interpreted here to be of cosmogenic origin.
? 2010 Elsevier B.V. All rights reserved.


http://www.scribd.com/doc/54164056/Fired-glaciofluvial-sediment-in-the-northwestern-Andes-Biotic-aspects-of-the-Black-Mat

Sedimentary Geology 237 (2011) 73-83

Fired glaciofluvial sediment in the northwestern Andes: Biotic aspects
of the Black Mat

William C. Mahaney a,?, David Krinsley b, Kurt Langworthy b, Volli
Kalm c, Tony Havics d,e, Kris M. Hart f,
Brian P. Kelleher f, Stephane Schwartz g, Pierre Tricart g, Roelf Beukens h

a Quaternary Surveys, 26 Thornhill Ave., Thornhill, Ontario, Canada L4J 1J4
b Department of Geological Sciences, University of Oregon, Eugene, OR
97403?1272, USA
c Institute of Ecology & Earth Sciences, Tartu University, Tartu
EE51014, Estonia
d pH2 LLC, 5250 E US 36, Suite 830, Avon, IN 46123, USA
e McCrone Institute, Chicago, IL, USA
f School of Chemical Sciences, Dublin City University, Glasnevin,
Dublin 9, Ireland
g IS Terre, CNRS, Universit? of Grenoble I, Grenoble, France
h IsoTrace Laboratory, Department of Physics, University of Toronto,
Toronto, Ontario, Canada M5S 1A7

a r t i c l e i n f o a b s t r a c t
Article history:
Received 31 July 2010
Received in revised form 2 February 2011
Accepted 16 February 2011
Available online 23 February 2011
Editor: M.R. Bennett
Keywords:
Chemistry of the Black Mat
Bacteria associated with fired sediment
Diagenesis of the fired material

Fired glaciofluvial beds in outwash considered to date from the onset
of the Younger Dryas Event (~12.9 ka) in the northwestern Venezuelan
Andes are considered equivalent to the Black Mat deposits described in
other areas of North and South America and Europe.
It may be equivalent to sediment recovered from other sites containing
beds with spikes of cosmic nuclides and charcoal indicating the
presence of widespread fire, one of the signatures of the Black Mat
conflagration that followed the proposed breakup of Comet Encke or an
unknown asteroid over the Laurentide Icesheet at 12.9 ka.
In the northern Andes at Site MUM7B, sediment considered coeval with
the Black Mat contains glassy carbon spherules, tri-coatings of C
welded onto quartz and feldspar covered with Fe and Mn.
Monazite with excessive concentrations of REEs, platinum metals
including Ru and Rh, possible pdf's, and disrupted/brecciated and
microfractured quartz and feldspar from impacting ejecta and excessive
heating summarize the data obtained so far.
The purpose of this paper is to document the physical character,
mineralogy and biotic composition of the Black Mat.
? 2011 Elsevier B.V. All rights reserved.

arkose at rogers.com (W.C. Mahaney).
krinsley at uoregon.edu (D. Krinsley),
klangwor at uoregon.edu (K. Langworthy),
volli.kalm at ut.ee (V. Kalm),
aahavics at pH2LLC.com (T. Havics),
hart.kris1 at gmail.com (K.M. Hart),
brian.kelleher at dcu.ie (B.P. Kelleher),
schwart at ujf-grenoble.fr (S. Schwartz),
pierre.tricart at ujf-grenoble.fr (P. Tricart),
roelf.beukens at utoronto.ca (R. Beukens),
_______________________________________________


The Usselo Horizon, a Worldwide Charcoal-Rich Layer of Aller?d Age,
Joh?n B. "Han" Kloosterman 1999 June, extensive references: Rich
Murray 2011.04.09
http://rmforall.blogspot.com/2011_04_01_archive.htm
Saturday, April 9, 2011
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Dennis Cox uses Mark Boslough, Sandia Lab, meteor air burst
supercomputer simulations to explain geoablation from Mexico to Canada
with many Google Earth images: Rich Murray 2011.04.09
http://rmforall.blogspot.com/2011_04_01_archive.htm
Saturday, April 9, 2011
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Rich Murray, MA
Boston University Graduate School 1967 psychology,
BS MIT 1964, history and physics,
1943 Otowi Road, Santa Fe, New Mexico 87505
505-501-2298 rmforall at comcast.net

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Received on Fri 29 Apr 2011 02:07:33 AM PDT