Meteorites from Mars have a history of interacting with water, likely as a result of melting of Mars’ ice due to volcanic activity more than 700 million years ago.
This discovery helps reveal the story of 800 grams (1.8 pounds) meteorite It remained a mystery for nearly 100 years, ever since it was discovered in a desk drawer at Purdue University in Indiana in 1931.
An international team of scientists led by Purdue University’s Marissa Tremblay has the answer. By dating water-denatured minerals in the Lafayette meteorite, researchers zeroed in on a date of 742 million years ago. However, according to Mars climate science, Mars’ liquid water generally disappeared More than 3 billion years ago. So where did water come from 742 million years ago?
The meteorite was named Lafayette, after the city where Purdue University is based. It’s unclear how it got into that drawer, but what we do know is where it originally came from. Mars And it once interacted with liquid water there. The question was how long ago that wet experience had happened.
“At this time, we do not believe that liquid water was abundant on the surface of Mars,” Tremblay said in the paper. statement. “Instead, we believe that 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. Masu.”
The Lafayette meteorite is a type of Martian meteorite known as a nacrite. It is made of igneous, or volcanic, rock and probably originated from a crater in the basaltic lava face near the extinct Elysium Mons volcano. Therefore, documenting the history of nacrite on Mars has become an important objective for planetary scientists.
Once upon a time, the Lafayette meteorite (and probably other nacrites as well) was blown off Mars. impact Then, it is sent into space while spinning, cosmic rays It irradiated the meteorite, forming isotopes that were determined to be 11 million years old, matching the age of the crater near Elysium Mons.
But when did the Lafayette meteorite arrive on Earth and how did it get into that drawer?
in previous paper Starting in 2022, researchers including Tremblay conducted some detective work to figure it out. They identified contamination with the mycotoxin deoxynivalenol, known as vomitoxin, a disease that affects crops.
“Using organic contaminants from Earth found at Lafayette, specifically crop diseases that were particularly prevalent in certain years, to determine when it fell and the possibility that the meteorite fall was witnessed by someone,” “We’ve narrowed down whether there is,” Tremblay said.
Tremblay and her colleagues concluded that Lafayette must have fallen in a crop field somewhere in rural Indiana around 1919, where a Purdue University student who may have witnessed Lafayette fall. discovered by. They took it back to college, but it ended up in that drawer, where it was discovered 12 years later. The rest, as they say, is history.
The results of this study were published in the journal Nov. 6. Geochemical perspective letter.
