[meteorite-list] Five Martian Meteorites Identified

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 09:55:55 2004
Message-ID: <200201291846.KAA07532_at_zagami.jpl.nasa.gov>

http://www.astronomy.com/Content/Dynamic/Articles/000/000/000/738mgdfw.asp

Five Martian Meteorites Identified

Some rocks found in Earth's hot and cold regions originally came from Mars.

by Vanessa Thomas
astronomy.com
January 29, 2002

Meteorite hunters have discovered five more Mars rocks on Earth, bringing
the total number of known martian meteorites to 24.

Several teams of Japanese, Chinese, and French researchers will discuss the
finds at the March 2002 Lunar and Planetary Science Conference near Houston,
Texas. Research team members and other meteorite hunters spotted the pieces
of Mars in the frigid ice of the Antarctic and in the hot sands of Africa's
Sahara desert.

The teams actually discovered many new rocks, but some were located near
each other and are so similar that the scientists believe they are pieces of
the same meteorites. One of two matching pieces is the second-largest
martian meteorite found so far. (The largest is the Zagami meteorite which
landed about 10 feet away from a Nigerian farmer who was chasing crows from
his corn field on an October afternoon in 1962.) Called Y000593, Japanese
researchers found the 13.7-kilogram (30.2-pound) space rock in a bare ice
field near Antarctica's Yamato Mountains in late November 2000. A few days
later, they found a second 1.3-kg (2.8-lb) meteorite - Y000749 - nearby.
Both have a greenish interior and an outer ("fusion") crust blackened while
falling through Earth's atmosphere.

Two other meteorites were found in Antarctica. A second Japanese team
reports that the 55-gram (1.9-ounce) meteorite they call YA1075 is nearly
completely stony with a dark green interior and a shiny, black fusion crust.
A Chinese expedition discovered GRV9927 near Grove Hill and describe the
9.97-g (0.4-oz) rock as being partially covered with a black fusion crust
and having a rounded triangular cone shape with thin, clear sections and
brown crystals.

In the Saharan sands of Morocco, French meteorite hunters recovered several
pieces of rock totaling 654 g (about 1.4 lbs) which scientists believe are
all part of one meteorite. Called NWA 1068 (or sometimes "Louise Michel"),
the meteorite is greenish-brown with no fusion crust, containing fine
grains and large crystals with volcanic inclusions.

The fifth meteorite, called Dhofar 378, was uncovered in Oman. A third
Japanese team reports that the 15-g (0.5-oz) rock contains a type of glass
that was likely formed by the shock of a large impact.

After examining the content of the rocks, the various research teams
realized that all the samples belong to a category called SNC meteorites, a
group of space rocks believed to have been blasted from Mars. The
shergottites, nakhlites, and chassignites are named after the first martian
meteorites discovered: Shergotty, Nakhla, and Chassigny found in 1865, 1911,
and 1815, respectively.
Received on Tue 29 Jan 2002 01:46:42 PM PST