[meteorite-list] Large impacts have a silver lining

From: Matthias Bärmann <majbaermann_at_meteoritecentral.com>
Date: Mon, 28 Jul 2008 17:15:48 +0200
Message-ID: <2563EBE46DCD4542912BF28674815773_at_thinkcentre>

Hi Darren, list,

yes, and much more: the transformation of impact-energy could solve the
planetary energy-problem l a s t i n g l y . Why not installing some dozens
of highly effective super-magnets in orbit? All expenses for anti-asteroid
programs could be spared etc.
;-)

Matthias


----- Original Message -----
From: "Darren Garrison" <cynapse at charter.net>
To: <meteorite-list at meteoritecentral.com>
Sent: Monday, July 28, 2008 4:40 PM
Subject: [meteorite-list] Large impacts have a silver lining


http://www.cosmosmagazine.com/news/2101/meteor-craters-may-hold-untapped-wealth

News
Meteor craters may hold untapped wealth
Monday, 28 July 2008by Heather Catchpole

Cosmos Online

SYDNEY: Meteorite impacts not only alter life on Earth, they alter the rocks
in
ways that can create valuable mining resources. Finding them could speed up
the
process of locating mineral wealth, says an Australian expert.

"It is not widely appreciated that an estimated 25 per cent of the world's
impact structures are associated in some way with economic or sub-economic
mineral and petroleum resources," said Peter Haines a sedimentologist with
the
Geological Survey of Western Australia.

"A better understanding and appreciation of impact as a geological process
may
accelerate the discovery of impact-related resources," said Haines who
presented
his research on the phenomenon last week on the final day of the Australian
Earth Sciences Convention 2008 in Perth.

Big holes hold large wealth

These resources include gold, platinum, diamond, nickel and petroleum. While
many mineral deposits have been recently recognised as having their origin
in
meteorite or comet impacts, locating the impact first and then looking for
mineral wealth could speed up the process, he said.

Many impact-related deposits are known around the world and are of
substantial
size. Examples include the Vredefort crater in the Free State Province of
South
Africa - the biggest and oldest impact crater on Earth and home of some of
the
world's richest gold deposits. The Sudbury Structure in Ontario, Canada, is
the
world's second-largest impact crater and hosts the world's largest deposit
of
nickel-platinum ore.

Western Australia has a number of impact structures, some of them buried
under
other rocks, which offered a future target for mineral exploration, said
Haines.

"Many geologists are not familiar with impact structures. They see impact
structures as something of academic interest and of no great economic
significance, but the case overseas clearly demonstrates that they can be of
considerable economic importance," said Haines.

Mineral resources can form immediately or some time after the impact, he
said.

Oil, gold and diamonds

For example: a shower of comets smashing into Siberia 36 million years ago
formed the Popagai crater and transformed the carbon-rich rocks into impact
diamonds. Minerals can also form from melted crust; the 10-kilometre-wide
meteorite that formed the Sudbury Structure in Canada created a pool of
molten
magma in which the heavy minerals nickel and platinum sunk and concentrated
in a
layer.

Fracturing in rocks from the intense shock pressure of impacts can also form
a
favourable environment for hydrothermal (hot-water) mineralisation, such as
gold
deposits. Buried impact structures, such as those found in the Gulf of
Mexico,
form favourable sites for oil, gas and petroleum reserves.

Rob Hough, a geochemist with CSIRO Exploration and Mining in Western
Australia,
has studied impact diamonds overseas. He said it was worth looking for
impact
mineralisation in Australia but that no exploration of this sort was
currently
happening. Haines' research is a "nice piece of work," he said, in that it
brings together a lot of information on impact structure mineralisation and
applies it to Australia.

"Certainly people have talked about looking for Sudbury analogues," said
Hough,
who noted that Australia's prolonged history of erosion may have removed
some of
the evidence of impact structures from the surface.


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Received on Mon 28 Jul 2008 11:15:48 AM PDT