[Rockhounds] Rocks From Mars Are Hitting Earth, And Something Is Odd About Their Age

[Kreigh Tomaszewski]

Humans are yet to set foot on Mars <https://www.sciencealert.com/mars>, but
over time, Mars has come to the humans. Chunks of Martian rock ejected from
their homeworld by processes such as violent impacts have wended their way
through the Solar System to end up – smack! – crashing into Earth.

As we collect these samples of our neighboring planet, a curious pattern
has emerged. Most of the samples seem to be rocks that formed on the red
planet fairly recently; a peculiarity, given most of the Martian surface is
so old.

It is possible the measures of age are largely wrong. Different dating
techniques have returned different results, which means scientists aren't
fully confident in estimates of when these rocks formed on Mars.

A team of scientists from the US and UK has now found a way to resolve this
problem. And, to their surprise, many of these rocks are indeed quite young
– just a few hundred million years old, in fact. This information could
provide clues about how long the meteorites took to get here, as well as
geological processes on Mars.

"We know from certain chemical characteristics that these meteorites are
definitely from Mars," says volcanologist Ben Cohen
<https://www.nhm.ac.uk/discover/news/2023/october/most-martian-meteorites-are-curiously-young-in-age.html>
of
the University of Glasgow, who led the research.

"They've been blasted off the red planet by massive impact events, forming
large craters. But there are tens of thousands of impact craters on Mars,
so we don't know exactly where on the planet the meteorites are from. One
of the best clues you can use to determine their source crater is the
samples' age."

https://www.sciencealert.com/rocks-from-mars-are-hitting-earth-and-something-is-odd-about-their-age