November 21, 2013
Examination Of Martian Meteorite Reveals Clues To Mars’ Ancient Past
April Flowers for redOrbit.com - Your Universe Online
A new study has uncovered what may be the first recognized example of ancient Martian crust.
The findings, published in Nature, are the work of Munir Humayun of Florida State University. His work is based on an analysis of a 4.4 billion-year-old Martian meteorite unearthed by Bedouin tribesmen in the Sahara desert. The rock, designated NWA 7533, might be the first recognized sample of ancient Martian crust and holds a wealth of information about the origin and age of Mars' crust.
Humayun, a professor in FSU's Department of Earth, Ocean and Atmospheric Science and a researcher at the National High Magnetic Field Laboratory (MagLab), and his collaborators performed complex analysis on the meteorite using an array of highly sophisticated mass spectrometers in MagLab's geochemistry department in order to detect minute amounts of chemicals.
"This cratered terrain has been long thought to hold the keys to Mars' birth and early childhood," Humayun said.
Although Mars' surface is more than half covered in craters, this is the first meteoric sample to come from this area. It is also the first time scientists have been able to understand the Red Planet's early crustal growth.
The research team was able to calculate the thickness of the Martian crust using chemical information found in pieces of soil contained within the meteorite. The findings of this analysis aligned with estimates obtained from independent spacecraft measurements, confirming that Mars did not experience a giant impact that melted the entire planet in its early history.
The team used a powerful microprobe at Curtin University in Perth, Australia to date special crystals within the meteorite — called zircons — at an astounding 4.4 billion years old.
"This date is about 100 million years after the first dust condensed in the solar system," Humayun said. "We now know that Mars had a crust within the first 100 million years of the start of planet building, and that Mars' crust formed concurrently with the oldest crusts on Earth and the Moon."
The scientists hypothesize that these trailblazing discoveries are just the beginning of what continued research will uncover. Humayun says that future studies may reveal more clues about the impact history of Mars, the nature of Martian zircons and the makeup of the earliest sediments on the Red Planet.