Mars meteorite called Black Beauty
Carl B. Agee (University of New Mexico)
Crystals within a Martian meteorite suggest Mars may have had abundant hydrothermal water when the rock formed 4.45 billion years ago.
The rock, called Black Beauty, was blown into space by an impact on Mars' surface and eventually crashed into the Sahara desert.
We already know a lot about Mars from the study of a meteorite discovered in Morocco in 2011, officially known as Northwest Africa 7034.
aaron cabosy Researchers at Curtin University in Perth, Australia, have been studying the tiny fragments, which contain zircon crystals 50 micrometers in diameter, for years.
Kavosie describes Black Beauty as “a rock that looks like a trash can.” Because it was formed by hundreds of pieces smashed together. “This is a great buffet of Martian history, with a mix of very old and very young rocks,” he says. “But much of the debris it contains belongs to some of the oldest rocks on Mars.”
The fragments studied by Kavosy and his team had crystallized in magma beneath Mars' surface. When they tested the zircons, they also found, unusually, that the elements iron, aluminum, and sodium were arranged in thin, onion-like layers.
“We wondered where else could we find elements like this in zircon crystals,” Kabosie says. The answer, he says, lies in South Australia's gold ore deposits. The zircon crystals there were nearly identical to those from Mars, including the same unusual combination of additional elements.
“This type of zircon is known to form only in places where hydrothermal processes or hydrothermal systems are active during igneous activity,” Kabosie says. “The hot water facilitates the transport of iron, aluminum, and sodium into the crystals as they grow layer by layer.”
Zircon has been exposed to multiple large-scale traumas, including the impact of an ancient collision and then another meteorite that hit the surface of Mars 5 to 10 million years ago and blasted Black Beauty into space have experienced. Despite these violent events, the rock's crystal structure is still intact at the atomic scale.
The lack of radiation damage means the extra elements were part of the crystal from the beginning, rather than being contaminated later, Kavosy said.
Eva Scherer Researchers at Stanford University in California believe that if this rock really formed in the presence of hydrothermal fluid and magma beneath the surface of Mars, water vapor entered the Martian atmosphere before rivers and lakes formed. This suggests that it may have been released.
“We're at a very old time, 4.5 billion years, when Mars was formed,” Scherrer said. “So this would be the earliest evidence of water behavior on Mars.”
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Source: www.newscientist.com
