MARTIAN METEORITE ROCKS!
Jan 04, 2013 (Albuquerque Journal - McClatchy-Tribune Information Services via COMTEX) --
A team of University of New Mexico scientists has discovered that a "mystery rock" is actually a meteorite from Mars, rich in water, that could open a new window for scientists on Earth's most interesting neighbor.
"This is really a once-in-a-lifetime meteorite," said Carl Agee on a recent afternoon as he showed visitors the rock in his office at UNM's Institute of Meteoritics.
The rock, catalogued by scientists as "Northwest Africa 7034," was an unexceptional mystery rock found in the desert of Morocco two years ago. It made its way to Albuquerque via an Indiana meteorite collector looking for help figuring out what it was. It was only when Agee and his colleagues vaporized a small sample in a UNM lab for analysis that they discovered that, not only was it from Mars, but it was a special rock indeed.
Agee and a group of colleagues are publishing their findings today on line with Science magazine. The rock formed in a Martian volcanic eruption 2.1 billion years ago, according to their analysis. At some point after that, it was blasted off the surface of mars when a giant meteorite hit that planet, kicking the humble rock into interplanetary space.
Then, a few hundred years ago -- exactly how long remains uncertain -- it slammed into Earth's atmosphere, fragmenting in the process, with pieces landing in the desert of north Africa. Meteorites are more often found in deserts than elsewhere because, after landing, they remain visible and relatively undisturbed for longer than they would in a wet climate.
Hap McSween at the University of Tennessee, an expert in interplanetary rocks, called it the most significant meteorite find in more than a decade. It provides important clues connecting data being gathered by NASA's robotic Mars rovers with analysis that can only be done on the rare Mars rocks that find their way to Earth, he said in a telephone interview Thursday.
Agee first got the three-quarter pound rock on loan in the summer of 2010 from Jay Piatek, an Indiana physician and meteorite collector who frequently works with the UNM research institute. Piatek got the stone from Moroccan rock hunters, but didn't know what it was.
The rock sat on a shelf in Agee's UNM office, puzzling the veteran meteorite researcher, because it was unlike other rocks he had studied.
When he finally got it in the lab down the hall, its trace chemistry made it quickly apparent that it was from somewhere besides Earth, according to Zachary Sharp, a UNM stable isotope geochemist who worked on the project.
"It's not from this planet," Sharp recalled telling Agee as they watched the data appear on a computer screen.
McSween, who is not involved in the research, said there is no doubt, based on the group's chemical analysis, that the sample bears the unique chemical signature of a rock from Mars.
The new find is the 112th known Martian meteorite found on Earth and available for scientific study. But among that group, Northwest Africa 7034 is unique. One of the 112 is an estimated 4 billion years old, and the other 110 are believed to have formed around 1 billion years ago, when Mars had already become a dry, icy planet.
Agee's find is smack in the middle of that gap at 2 billion years old, near to a period of Martian history scientists called the "Amazonian." As its name implies, that is a period when Mars is believed to have been much wetter, and Agee's new rock fits that model. It is common for rocks to have traces of water trapped inside when they are made. But Agee's meteorite has 10 times as much water as other Martian meteorites.
That suggests that the volcano that made it pushed its lava up through some sort of water, Agee said in an interview -- perhaps a layer of permafrost soil.
"It's also possible that there was a groundwater system present, or maybe even surface water," he said.
With the initial analysis now published, scientists are diving into more detailed studies of the rock. McSween is among more than a dozen researchers asking for samples to analyze, and Agee and his UNM colleagues are in the midst of probing the samples more deeply to see what additional secrets the rare rock from Mars might reveal.
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