‘Black Beauty’ looks great for her age! ~ 2.1 Billion Year Old Meteorite from Mars

NWA 7034 could help scientists piece together a previously unstudied time in Martian geologic history.

NWA 7034 could help scientists
piece together a previously unstudied time in Martian geologic history.

smh.com.au 

WASHINGTON — A fist-sized meteorite
nicknamed “Black Beauty” could unlock vital clues to the evolution of
Mars from the warm and wet place it once was to its current cold and dry
state, NASA says.

Discovered in Morocco’s Sahara Desert in 2011,
the 11-ounce (320-gram) space rock contains 10 times more water than
other Martian meteorites and could be the first ever to have originated
on the planet’s surface or crust.

After more than a year of
intensive study, a team of US 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, NASA said on Thursday.

The
abundance of water molecules in the meteorite – about 6000 parts per
million, 10 times more than other known rocks – suggests water activity
persisted on the Martian surface when it was formed.


It is generally accepted that Mars had abundant water early in its
existence – scientists ponder if life might once have existed there –
but the nature of its evolution to a cold and dry place remains a
mystery.

“Many scientists think that Mars was warm and wet in its
early history, but the planet’s climate changed over time,” lead
scientist Carl Agee, whose study was published in Science Express, told Space.com.

Known
technically as NWA (Northwest Africa) 7034, “Black Beauty” is made of
cemented fragments of basalt, a rock that forms from rapidly cooled
lava.

“Perhaps most exciting is that the high water content could
mean there was an interaction of the rocks with surface water either
from volcanic magma, or from fluids from impacting comets during that
time,” co-author Andrew Steele said.

“It is the richest Martian meteorite geochemically and further analyses are bound to unleash more surprises.”
Unlike
most Martian meteorites, it is thought to be from the planet’s surface,
not deeper inside, as its chemistry matched surface rocks NASA has
studied remotely via Mars rovers and orbiting satellites.

“Researchers
theorise the large amount of water contained in NWA 7034 may have
originated from interaction of the rocks with water present in Mars’
crust,” NASA said.

“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.”

More
than 100 Martian meteorites have been discovered on Earth to date but
most come from three meteorites: Shergotty, Nakhla, and Chassigny.

NWA
7034 has unique characteristics and it took scientists several months
to ascertain that it did indeed come from Mars and not another planet,
or from an asteroid belt.

“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.”
Agee echoed those comments.
“This
Martian meteorite has everything in its composition that you’d want in
order to further our understanding of the Red Planet,” he said, noting
that it “tells us what volcanism was like on Mars two billion years
ago”.

“It also gives us a glimpse of ancient surface and
environmental conditions on Mars that no other meteorite has ever
offered,” Agee added.

It was not until the 1980s that scientists
were able to determine the origin of meteorites by analyzing small
pockets of atmospheric gas trapped inside.

Gases are released by
heating the rock in a laboratory and then analyzed and compared, in this
case, to the information gathered by probes orbiting Mars or on its
surface.

The latest probe, the Curiosity rover — the most
sophisticated ever sent to another planet — has since August been
searching for signs the planet was ever suitable for microbial life.

“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.”

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