A Martian meteorite nicknamed Black Beauty
Carl B. Agee (University of New Mexico)
Crystals inside a Martian meteorite hint that there may have been plenty of hot water on Mars when the rock formed 4.45 billion years ago.
The rock, nicknamed Black Beauty, was blasted into space by the impact on the surface of Mars before eventually crashing into the Sahara desert.
It has a lot by studying the meteorite we have learned about MarsIt was discovered in Morocco in 2011 and is formally known as Northwest Africa 7034.
Aaron Cavosi At Curtin University in Perth, Australia, and his colleagues have been studying a small part of it for years, including a zircon crystal measuring 50 micrometers.
Cavosi describes Black Beauty as a “garbage can” rock because it was formed from hundreds of fragments smashed together. “It’s a wonderful buffet of Martian history, a mix of very old and very young rocks,” he says. “But a lot of the fragments that are there are from the oldest pieces of rock on Mars.”
The piece that Cavosi and his team studied crystallized in magma beneath the Martian surface. When they analyzed zircon, they found that, unusually, it also contained the elements iron, aluminum and sodium, neatly arranged in thin layers like an onion.
“We asked, where else do you find elements like this in a zircon crystal?” says Cavosi. The answer lay in a gold ore deposit in South Australia, where the zircon crystals were nearly identical to those from Mars, including the same unusual combination of accessory elements.
“These types of zircons only form where hydrothermal processes, hot water systems, are active during magmatism,” says Cavosi. “The hot water facilitates the transport of iron, aluminum and sodium into the crystal as it grows, layer by layer.”
Zircon has suffered a number of horrific traumas, including being hit by an ancient impact event, and later by another meteorite that hit the surface of Mars between 5 million and 10 million years ago, throwing the Black Beauty into space. Despite these violent events, the rock’s crystal structure is intact at the atomic scale.
The lack of radiation damage means the extra elements were part of the crystal to begin with, rather than contaminating it later, Cavosi says.
Eva Scheller If the rock formed in the presence of hot water and magma on the surface of Mars, it suggests that water vapor may have been released into the Martian atmosphere before rivers and lakes formed, says Stanford University in California.
“At the age of 4.5 billion years old, we are at the time when Mars was formed,” says Scheller. “So this would mark evidence of some of the earliest behavior of water on Mars.”
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