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| Designated Northwest Africa (NWA) 7034, and nicknamed "Black Beauty," the Martian meteorite weighs approximately 11 ounces (320 grams). [PHOTO: NASA] |
Washington: NASA-funded researchers analyzing a small meteorite that may
be the first discovered from the Martian surface or crust have found it
contains 10 times more water than other Martian meteorites from unknown
origins.
This new class of
meteorite was found in 2011 in the Sahara Desert. Designated Northwest Africa
(NWA) 7034, and nicknamed "Black Beauty," it weighs approximately 11
ounces (320 grams). After more than a year of intensive study, a team of U.S.
scientists determined the meteorite formed 2.1 billion years ago during the
beginning of the most recent geologic period on Mars, known as the Amazonian.
"The age of NWA
7034 is important because it is significantly older than most other Martian
meteorites," said Mitch Schulte, program scientist for the Mars
Exploration Program at NASA Headquarters in Washington. "We now have
insight into a piece of Mars' history at a critical time in its
evolution."
The meteorite is an
excellent match for surface rocks and outcrops NASA has studied remotely via
Mars rovers and Mars-orbiting satellites. NWA 7034's composition is different
from any previously studied Martian meteorite. The research is published in
Thursday's edition of Science Express.
"The contents of
this meteorite may challenge many long held notions about Martian
geology," said John Grunsfeld, associate administrator for NASA's Science
Mission Directorate in Washington. "These findings also present an
important reference frame for the Curiosity rover as it searches for reduced
organics in the minerals exposed in the bedrock of Gale Crater."
NWA 7034 is made of
cemented fragments of basalt, rock that forms from rapidly cooled lava. The
fragments are primarily feldspar and pyroxene, most likely from volcanic
activity. This unusual meteorite's chemistry matches that of the Martian crust
as measured by NASA's Mars Exploration Rovers and Mars Odyssey Orbiter.
"This Martian
meteorite has everything in its composition that you'd want in order to further
our understanding of the Red Planet," said Carl Agee, leader of the
analysis team and director and curator at the University of New Mexico's
Institute of Meteoritics in Albuquerque. "This unique meteorite tells us
what volcanism was like on Mars 2 billion years ago. It also gives us a glimpse
of ancient surface and environmental conditions on Mars that no other meteorite
has ever offered."
The research team
included groups at the University of California at San Diego and the Carnegie
Institution in Washington. Experiments were conducted to analyze mineral and
chemical composition, age, and water content.
Researchers theorize
the large amount of water contained in NWA 7034 may have originated from
interaction of the rocks with water present in Mars' crust. The meteorite also
has a different mixture of oxygen isotopes than has been found in other Martian
meteorites, which could have resulted from interaction with the Martian
atmosphere.
Most Martian
meteorites are divided into three rock types, named after three meteorites;
Shergotty, Nakhla, and Chassigny. These "SNC" meteorites currently
number about 110. Their point of origin on Mars is not known and recent data
from lander and orbiter missions suggest they are a mismatch for the Martian
crust. Although NWA 7034 has similarities to the SNC meteorites, including the
presence of macromolecular organic carbon, this new meteorite has many unique
characteristics.
"The texture of
the NWA meteorite is not like any of the SNC meteorites," said co-author
Andrew Steele, who led the carbon analysis at the Carnegie Institution's
Geophysical Laboratory. "This is an exciting measurement in Mars and
planetary science. We now have more context than ever before to understanding
where they may come from."