[meteorite-list] Meteorite In Situ On Mars

From: Meteorites USA <eric_at_meteoritecentral.com>
Date: Thu, 04 Jun 2009 10:38:48 -0700
Message-ID: <4A2806A8.1070109_at_meteoritesusa.com>

Hi List,

Here's a cool article on NewScientist.com showing a photo taken by
Opportunity Rover of a possible meteorite about 800 meters south of
Victoria Crater.

http://www.newscientist.com/data/images/ns/cms/dn17254/dn17254-1_300.jpg

ARTICLE: Fist-sized stones scattered around Victoria Crater on Mars
appear to be meteorites ? and might be fragments of the object that
punched out the crater, researchers say. Because the rocks contain iron,
which rusts in the presence of water, they could provide a sensitive
gauge of how much weathering has affected the region in recent times.

The rovers Spirit and Opportunity have previously found three iron
meteorites, whose shiny, metallic appearance makes them stand out
against the dusty Martian surface.

Now, Opportunity has turned up six other candidates on a Martian plain
called Meridiani Planum, all of which appear to be related to each
other. Instruments on the rover, including its M?ssbauer spectrometer,
show the rocks are stony, but also contain iron-bearing minerals present
in meteorites found on Earth, such as kamacite and troilite.

"I've been very excited ? about the prospects of finding meteorites at
the Opportunity landing site because it is the perfect setting for it ?
an ancient surface with very few Mars rocks," says James Ashley of
Arizona State University in Tempe. "In this sense, it is similar to
Antarctic meteorite fields where few Earth rocks are to be found."

http://www.newscientist.com/article/dn17254-rusty-space-rocks-could-flag-up-mars-water.html

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In an old article linked from this one is another describing two iron
meteorites found by Spirit rover in April of 2006.

IRON METEORITES: Two iron meteorites have been spotted by the Mars rover
Spirit, mission scientists have announced. The finds are the first
meteorites identified by Spirit, although its twin, Opportunity,
discovered a similar space rock on the other side of the planet in
January 2005.

Spirit photographed the rocks in April 2006, just after it parked at Low
Ridge Haven, a northern-tilting slope that is serving as its home for
the six-month-long Martian winter.

The rocks appear smoother and lighter in tone than surrounding rocks.
They resemble the glossy, pitted meteorite - dubbed "Heat Shield Rock" -
that Opportunity found near its discarded heat shield.

Observations of that rock with Opportunity's miniature thermal emission
spectrometer (Mini-TES) showed it was very reflective - a telltale sign
of an iron meteorite (see Metal chunk on Mars confirmed as meteorite).
Now, observations by the Mini-TES on Spirit reveal the two suspect rocks
are similarly reflective.

"They're very good reflectors," says mission member Ray Arvidson of
Washington University in St Louis, US. "We're seeing the heat of the sky
being reflected to Mini-TES. I don't know how that can happen unless
it's a metal."

http://www.newscientist.com/article/dn9324-mars-rover-spirit-finds-metallic-meteorites.html

-- 
Regards,
Eric Wichman
Meteorites USA
http://www.meteoritesusa.com
904-236-5394

Received on Thu 04 Jun 2009 01:38:48 PM PDT