Scientist uncovers red planet's climate history in unique meteorite

PUBLIC RELEASE DATE:

27-Aug-2014

Contact: Munir Humayun Humayun@magnet.fsu.edu 850-544-5740 Florida State University

TALLAHASSEE, Fla. Was Mars now a cold, dry place once a warm, wet planet that sustained life? And if so, how long has it been cold and dry?

Research underway at the National High Magnetic Field Laboratory may one day answer those questions and perhaps even help pave the way for future colonization of the Red Planet. By analyzing the chemical clues locked inside an ancient Martian meteorite known as Black Beauty, Florida State University Professor Munir Humayun and an international research team are revealing the story of Mars' ancient, and sometimes startling, climate history.

The team's most recent finding of a dramatic climate change appeared in Nature Geoscience, in the paper "Record of the ancient Martian hydrosphere and atmosphere preserved in zircon from a Martian meteorite."

The scientists found evidence for the climate shift in minerals called zircons embedded inside the dark, glossy meteorite. Zircons, which are also abundant in the Earth's crust, form when lava cools. Among their intriguing properties, Humayun says, is that "they stick around forever."

"When you find a zircon, it's like finding a watch," Humayun said. "A zircon begins keeping track of time from the moment it's born."

Last year, Humayun's team correctly determined that the zircons in its Black Beauty sample were an astonishing 4.4 billion years old. That means, Humayun says, it formed during the Red Planet's infancy and during a time when the planet might have been able to sustain life.

"First we learned that, about 4.5 billion years ago, water was more abundant on Mars, and now we've learned that something dramatically changed that," said Humayun, a professor of geochemistry. "Now we can conclude that the conditions that we see today on Mars, this dry Martian desert, must have persisted for at least the past 1.7 billion years. We know now that Mars has been dry for a very long time."

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Scientist uncovers red planet's climate history in unique meteorite