Mars Meteorite May Be Missing Link to Red Planet's Past

NWA 7034
NWA 7034 could help scientists piece together a previously unstudied time in Martian geologic history. (Image credit: Carl Agee)

A Martian meteorite recently found on Earth may represent a missing link between Mars' warm, wet past and its present cold and dry state, a new study shows.

The rock, which was discovered in Morocco in 2011, is of a previously unknown class that could fill in gaps in scientists' understanding of the Red Planet's geological history, researchers said.

The meteorite — named NWA 7034 — is markedly dissimilar from other meteorites from Mars that scientists have studied on Earth.

Rare type

NWA 7034 has about 10 times more water content (about 6,000 parts per million) than any of the 110 other known meteorites that have fallen to Earth from Mars, suggesting that the meteorite probably came from the Martian surface, as opposed to deeper inside, said University of New Mexico planetary scientist Carl Agee, lead author of a paper describing the findings published in the Jan. 3 issue of the online journal Science Express.

Previously studied Martian meteorites, known as the SNC samples, appear to come from a different, less explored part of the Martian landscape. They probably broke away from Mars after a large asteroid impacted a certain region of the planet. But this newest sample is more representative of Mars's surface, Agee told [Mars Meteorites: Pieces of the Red Planet on Earth (Photos)]

The researchers think NWA 7034 represents the remains of a volcanic eruption on the Martian surface that occurred about 2.1 billion years ago. The meteorite was once lava from the eruption that cooled and hardened on the surface of the planet. The rock's cooling was probably aided by water on Mars' surface that was eventually imprinted on the chemical composition of the meteorite.

NWA 7034, found in Northwest Africa, has 10 times the water content of other previously found Martian meteorites. (Image credit: Carl Agee)

Middle-aged rock

The meteorite's age is also of interest to scientists. Most of the SNC meteorite samples date to only around 1.3 billion years ago, with the oldest being about 4.5 billion years old. NWA 7034 represents a transition between the oldest and youngest Martian meteorite samples found on Earth, Agee said.

"Many scientists think that Mars was warm and wet in its early history, but the planet's climate changed over time," Agee said. Eventually, the Red Planet lost its atmosphere and became the cold, dry desert it is today. The new meteorite comes from the transitional period between these extremes, making it an important find for scientists hoping to learn how the Martian climate change occurred.

Agee's conclusions are supported by data collected by the Mars rover missions and spacecraft in orbit around the planet, he said. The geochemical composition of the new meteorite falls in line with the rocks that rovers have analyzed on the surface of the Red Planet.

The researchers confirmed the meteorite's Martian origins using a process of elimination. It took six months for Agee and his team to confidently report that the piece of space rock came from Mars. Because of the meteorite's age, they knew it couldn't come from an asteroid: All asteroids are much older than 2.1 billion years — most are probably at least 4.5 billion years old.

"We knew that it had to be from a planet," Agee said. Mercury wasn't an option: the composition of the volcanic meteorite didn't match the surface of the closest planet to the sun. Venus didn't fit either. Scientists hypothesize that that planet's surface is too dry to produce a meteorite with NWA 7034's water content, Agee added.

Mars was the only viable option, and with mounting evidence suggesting that the meteorite was similar in composition to the rocks analyzed by rovers, Agee's hypothesis fit.

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Miriam Kramer
Staff Writer

Miriam Kramer joined as a Staff Writer in December 2012. Since then, she has floated in weightlessness on a zero-gravity flight, felt the pull of 4-Gs in a trainer aircraft and watched rockets soar into space from Florida and Virginia. She also served as's lead space entertainment reporter, and enjoys all aspects of space news, astronomy and commercial spaceflight.  Miriam has also presented space stories during live interviews with Fox News and other TV and radio outlets. She originally hails from Knoxville, Tennessee where she and her family would take trips to dark spots on the outskirts of town to watch meteor showers every year. She loves to travel and one day hopes to see the northern lights in person. Miriam is currently a space reporter with Axios, writing the Axios Space newsletter. You can follow Miriam on Twitter.