[meteorite-list] He doesn't look a day over 2 billion... (involves the big-a*** Kalahari lunar)

From: Darren Garrison <cynapse_at_meteoritecentral.com>
Date: Wed, 05 Dec 2007 09:53:21 -0400
Message-ID: <i4bdl35gvinfrb3jgoajdhfmr31qis1vih_at_4ax.com>

http://www.arabtimesonline.com/client/pagesdetails.asp?nid=8973&ccid=18

Man in the Moon is four billion years old
  
PARIS, Dec 5, 2007 (AFP) - The plains of solidified lava that give the Moon its
quirky human-like face as seen from Earth were created more than four billion
years ago, according to a paper appearing on Thursday in Nature, the British
science weekly.

The evidence comes from an unearthly silvery-grey stone that was blasted off
from the face of the Moon, perhaps by an impacting asteroid, and was then
captured by Earth's gravity, prompting it to fall to ground in Botswana.

In 1999, the 13.5-kilo (29.7-pound) remnant of this roving rock was found by
local people near the village of Kuke, in the grasslands of the Kalahari Nature
Reserve, who then sold it to meteorite hunters.

The lunar heritage of the rock, named Kalahari 009, has been confirmed by a
telltale signature of oxygen isotopes and ratio of iron to manganese in two
volcanic minerals, olivine and pyroxene.

The nature of these chemicals puts the rock into the category of a mare basalt
-- a lava that flowed out smoothly onto the lunar surface before solidifying,
forming dark plains that early skywatchers mistakenly took for seas, 'Mare' in
Latin.

A new analysis of fragments of phosphate in Kalahari 009 puts the rocks at the
whopping old age of 4.35 billion years, give or take 150 million years, the
Nature study says.

This implies that mare-type volcanism must have occurred at least as early as
this date, just after the first stage of lunar crust formation, say the authors,
led by Kentaro Terada of Hiroshima University in Japan and Mahesh Anand of
Britain's Open University.

Mare volcanism overlapped with a later stage of volcanism, evidence of which was
found in rocks picked up by the Apollo missions.

The 'Man in the Moon' comprises eyes made of the Mare Imbrium and Mare
Serenitatis, a nose consisting of Sinus Aestuum, while the Mare Nubium and Mare
Cognitum provide its mouth.

These and other mare account for nearly a sixth of the lunar surface, mostly on
the side visible from Earth.
 
Received on Wed 05 Dec 2007 08:53:21 AM PST