The birthplace of the oldest known Martian meteorite may have been located on the Red Planet.
Discoveries may reveal clues to the origins of March, Earth and the other terrestrial planets of the solar system.
In a new study, scientists have analyzed the 11-ounce (320-gram) NWA 7034 meteorite, nicknamed “black beauty“, which was discovered in Morocco in 2011. Like more than 300 other rocks that have fallen to Earth from space, NWA 7034 is from Marsblown off the red planet by cosmic impacts.
Related: Chances of early life on Mars faced a meteorite problem
Previous research has revealed that NWA 7034 is the oldest known Martian meteorite, dating to around 4.5 billion years ago. It is also the only so-called brecciated Martian sample available on Earth, meaning it contains angular fragments of several rock types cemented together. In contrast, all other known Martian meteorites contain unique rock types.
Until now, scientists did not know precisely where NWA 7034 came from on Mars. Now, researchers may have pinpointed Black Beauty’s exact point of origin.
In the new study, scientists used supercomputers to analyze images of the Martian surface. “My team and I have developed a crater detection algorithm to detect all impact craters, up to about 100 meters [330 feet] in diameter, seen in high-resolution images covering the surface of Mars, or about 94 million in total,” study lead author Anthony Lagain, a planetary scientist at Curtin University in Perth, told Space.com. , in Australia.
When researchers studied the size and location of these craters, they realized that most of the smaller craters were scattered around larger craters over 3 kilometers wide and less than 10 million years old. These findings suggest that these small craters were formed by debris from larger impacts after they fell to the surface. The relatively recent origin of all these craters helped explain why the smaller ones were still detectable: millions of years of erosion and other activity on Mars had not yet erased them.
Scientists have identified 19 craters (opens in a new tab) as the most likely origin points of Martian meteorites on Earth. When they compared the properties of these craters with those of NWA 7034, they found only one crater matched, Lagain said. They named this crater after the Australian town of Karratha, home to one of the oldest rocks on Earth.
The findings suggest that the oldest fragments of NWA 7034 were probably mined from Mars 1.5 billion years ago by the cosmic impact that formed the 40 km wide Khujirt crater in the southern hemisphere. of the red planet. These ancient fragments, along with the rest of NWA 7034, were then thrown off Mars by a subsequent impact 5 to 10 million years ago, which formed the Karratha crater.
“The origin of Martian meteorites was an old puzzle,” Lagain said. Discovering the birthplace of one is “roughly equivalent to a free sample return mission,” he noted.
“We now know the rock is from the Terra Cimmeria-Sirenum province,” Lagain said. “This region holds the clues to understand[ing] the first stage of evolution and differentiation of the planet. If we want to understand how Mars formed and evolved, then we need to analyze this province much more than we do now.”
The results suggest that sending a rover or drone to this region “would help us understand what happened 4.5 billion years ago on Mars”, shortly after the Red Planet, the earth and the solar systemit’s different rocky worlds were born, Lagain said. This information, in turn, can help “fill the knowledge gap for the same time period on Earth.”
The scientists detailed their findings online July 12 in the journal Nature Communication (opens in a new tab).
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