Current insights into the Red Planet's evolution stem largely from spacecraft observations and meteorite analysis. These meteorites, primarily found in deserts and Antarctica, were once part of Mars before being ejected into space and eventually landing on Earth. They fall into two distinct categories: shergottites and nakhlites, each offering contrasting views of Mars' geological past.

A recent study published in the *Proceedings of the National Academy of Sciences* highlights the potential for sample return missions to clarify these conflicting narratives. Researchers at Lawrence Livermore National Laboratory (LLNL) emphasize the importance of analyzing samples collected directly from known locations on Mars.

"We are currently using samples that are often smaller than the tip of your thumb to extrapolate the entire evolutionary history of a planet. You would not predict the existence of the Himalayas from a sample collected in the ocean basin," said LLNL researcher Lars Borg. "We need to be able to determine if the characteristics we see are part of a large-scale feature or just some small local anomaly."

Shergottites, dating back 200 to 600 million years, are basaltic rocks with geochemical and isotopic properties resembling those of the moon. These samples suggest Mars formed a core, mantle, and crust early in its history, remaining geologically inactive since then. On the other hand, nakhlites, which are 1.3 billion years old, indicate that Mars developed these layers even earlier and experienced ongoing geological activity akin to Earth. This duality makes Mars a particularly enigmatic planet.

At LLNL, the Cosmochemical and Isotopic Signatures group has conducted extensive analysis and dating of Martian meteorites. The team is now upgrading its facilities in preparation for NASA's Mars Sample Return Campaign, which will deliver samples collected by the Perseverance rover back to Earth.

"This is part of a much broader agenda for LLNL to contribute our unique analytical capabilities to upcoming sample return missions, which importantly include the return of humans to the moon through the Artemis program," explained LLNL researcher Thomas Kruijer.

By studying these Martian samples and their specific locations, Borg and his team aim to develop a comprehensive model of the planet's formation and evolution. Such understanding could provide valuable insights into Earth's own history and the broader processes shaping terrestrial planets.

"Obtaining samples from the only place in the solar system that even remotely looks like Earth could illuminate how our world came to be, explain how civilization formed and examine whether we are alone in the universe," Borg said.

Related Links
NASA Mars Sample Return Campaign
Mars News and Information at MarsDaily.com
Lunar Dreams and more