Wow, that's a big event.
http://www.sciencedirect.com/science?
_ob=ArticleURL&_udi=B6V93-4XHVGW7-1&_user=10&_coverDate=03%2F15%
2F2010&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_acct=C
000050221&_version=1&_urlVersion=0&_userid=10&md5=62d1dd4fb0e08c37ecf1a2
bf25b0f66d
http://tinyurl.com/yaeodb4
doi:10.1016/j.geomorph.2009.10.007
W.C. Mahaney et al., W.C.,Oct,2009,Geomorphology,"Evidence from the
northwestern Venezuelan Andes for extraterrestrial impact: The black
mat enigma"
ABSTRACT:
"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 Clovis Age sites in North America, falling within
the range of ‘black mat’ 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 cm above 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 Allerød 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."
Best regards,
Horace Heffner
http://www.mtaonline.net/~hheffner/
