Ancient Martian Meteorite Suggests Early Wet Climate

Scientists have identified a 4.1-billion-year-old meteorite recovered from the Sahara desert near the village of Bir Chali as one of the oldest known rocks from Mars. The coarse-grained igneous gabbro, composed of feldspar, pyroxene and uranium-bearing zircon, appears to have formed in the Martian crust, likely in the southern highlands near the Hellas Basin.

Only three Martian meteorites are known to date back to the planet’s early history, and researchers say the new sample, designated Teghaza 001, may be older than the well-studied Antarctic meteorite discovered in 1984.

"A witness to a time when Mars was likely warmer and wetter than it has been for most of its history," said planetary scientist Yang Liu of NASA's Jet Propulsion Laboratory.

Isotopic analysis of hydrogen and oxygen in the rock indicates that liquid surface water percolated deep into the crust and interacted with molten mantle material more than 4.1 billion years ago. Liu added that multiple lines of evidence, including hydrogen isotopes in phosphate and oxygen isotopes in minerals, support the presence of water on Mars at that time.

Co-author Lee Saper of NASA's Ames Research Center and the BAER Institute noted that the findings reinforce the hypothesis that early Mars possessed a thicker atmosphere and conditions that could have supported microbial life, though the study does not directly address the existence of life on the planet.