Eleven million years ago, an asteroid hit Mars, sending debris flying through space. One of these masses eventually crashed into Earth. During initial investigation of this object, lafayette meteoritescientists discovered that it interacted with liquid water while on Mars. Now, researchers from the US and UK have determined the age of minerals in meteorites that formed when liquid water was present.
The Lafayette meteorite was scraped off the surface of Mars and then spent about 11 million years flying through space. It finally ended up in a drawer at Purdue University in 1931 and has been teaching scientists about Mars ever since. Image credit: Purdue Brand Studio.
A meteorite is a solid time capsule from a planet or celestial body in the universe.
They carry bits of data that can be unlocked by geochronologists.
They are distinguished from rocks you might find on Earth by the crust they form as they fall into the atmosphere, often forming a fiery portal visible in the night sky.
“We can identify meteorites by studying what minerals are in them and the relationships between these minerals,” said researcher Dr. Marissa Tremblay. states. purdue university.
“Meteorites are often denser than Earth's rocks, contain metals, and are magnetic.”
“We can also look for things like the fusion crust that forms when we enter Earth's atmosphere.”
“Finally, we can use the chemical properties of meteorites (particularly their oxygen isotope composition) to determine which planet they came from or what type of meteorite they belong to. ”
According to the authors, some Martian meteorites, such as the 0.8 kg Nacritite meteorite called the Lafayette meteorite, contain minerals that were formed by interaction with liquid water while on Mars. That's what it means.
“So by dating these minerals, we can tell when in Mars' geological past there was liquid water on or near the surface of Mars,” Tremblay said. .
“We dated these minerals in the Martian meteorite Lafayette and found that they formed 742 million years ago.”
“At this point, we don't think there was an abundance of liquid water on the surface of Mars.”
“Instead, we believe this water comes from melting nearby underground ice called permafrost, and that permafrost thaw is caused by magmatic activity that continues to occur regularly on Mars. ”
Researchers say the age derived from the timing of water-rock interactions on Mars is robust and the chronometer used is not affected by events that happened to the Lafayette meteorite, which changed in the presence of water. It was proved that.
“This age could be due to the impact of the Lafayette meteorite being ejected from Mars, the heating Lafayette experienced during its 11 million years floating in space, or the heating Lafayette experienced when it fell to Earth and burned up a bit. “in Earth's atmosphere,'' Dr. Tremblay said.
“But we were able to demonstrate that none of these things affected the chronology of water quality changes in Lafayette.”
“This meteorite has unique evidence that it interacted with water,” said Dr. Ryan Ickert, also of Purdue University.
“The exact date of this is controversial, and our publication dates from a time when water existed.”
“We know this because after this meteorite was ejected from Mars, it was bombarded with cosmic ray particles in space, producing specific isotopes at Lafayette,” Tremblay said. said.
“Many meteoroids are produced by impacts on Mars and other planets, but only a handful end up falling on Earth.”
of findings Published in this month's magazine Geochemical perspective letter.
_____
MM Tremblay others. 2024. Dating recent water activity on Mars. Letter from a geochemical perspective 32;doi: 10.7185/geochemlet.2443
Source: www.sci.news
