Discovered in the Sahara desert in Algeria in 2019, a Martian meteorite designated Northwest Africa 13441 has been dated to 1.27 billion years ago. Scientists say the rock helps bridge a 1.8 billion-year gap in Mars’ history, offering fresh clues about the Red Planet’s early magmatic and volcanic activity.
A Martian rock flung into space and recovered in the Sahara desert has given researchers a look into a long-hidden chapter of the Red Planet’s past. Designated Northwest Africa 13441, the meteorite was discovered in Algeria in 2019. A team of scientists analyzed a 0.03-ounce sample from the rock in the lab, determining it dates back to 1.27 billion years ago.
The findings, published in the journal Geochimica et Cosmochimica Acta, address a persistent blind spot in planetary science. Impacts on Mars occasionally send fragments into space, and approximately 400 Martian specimens have been identified on Earth. Before this analysis, however, none of those specimens had been dated between 600 million and 2.4 billion years ago. The most common category of Martian meteorites, known as shergottites, typically date back to around 600 million years, with two known samples dating to roughly 2.4 billion years old. That left a nearly 2 billion-year gap in the geological record of Mars.
Unlocking a 1.8 Billion-Year Geological Gap in Mars History
Because researchers cannot choose which Martian rocks happen to land on Earth, they must rely on chance discoveries to piece together planetary evolution. To determine the age of Northwest Africa 13441, the research team compared its chemical composition against other Martian rocks. While its composition aligned with shergottites, scientists also detected traces of neodymium, a rare-earth metal typically found in chondrites—a different class of meteorite that usually dates back to the early formation of the solar system 4.5 billion years ago.
“The characteristics of this meteorite were entirely surprising,” Ethan Baxter, an Earth and environmental science professor at Boston College and co-author of the study, said. “No other martian meteorite like this has an age of 1.27 billion years old.”
Ethan Baxter, Earth and environmental science professor at Boston College and co-author of the study
Scientists date rocks to when they solidified from magma. Researchers believe Northwest Africa 13441 formed near the boundary separating the Martian crust and mantle before a volcano ejected it roughly 1.27 billion years ago, allowing it to solidify on the surface. While older Martian meteorites dating back more than 4 billion years have been recovered, this specimen belongs to the shergottite class.
Clues From Pristine Magmatic Reservoirs on the Red Planet
Mars reached its full size relatively quickly, completing its formation in less than 5 million years after the solar system began. Unlike Earth, Mars lacks plate tectonics, meaning its early-formed composition has remained relatively unaltered.
The dual characteristics found in Northwest Africa 13441—sharing traits of both shergottites and chondrites—suggest that deep interior regions of Mars remained relatively unaltered by subsequent geological processes. According to the published study, the chondritic composition points toward a previously unsampled reservoir on Mars, or alternatively, a hybrid mix of enriched and depleted shergottites.
Researchers hope the sample will yield valuable data regarding magmatic and volcanic activity during the 2 billion-year gap, ultimately clarifying the early environmental processes that shaped the Red Planet as the solar system evolved.
Ещё по этой теме
