Paleometeorite
A paleometeorite is a meteorite that fell to Earth in the distant geological past and has been preserved in rock.
A paleometeorite is a meteorite that landed on Earth long ago, typically more than a million years, and survived in a geological deposit. Because meteorites weather quickly on Earth's surface, such old finds are rare and usually heavily altered.
Examples include meteorites preserved in old sediments and soils. Some iron meteorites found in deserts or buried in gravels have terrestrial ages of hundreds of thousands of years, but true paleometeorites are older still. They are particularly valuable for understanding how the kinds of meteorite falling on Earth have changed over time.
The most famous are the fossil meteorites from Ordovician limestone in Sweden, around 467 million years old, though these have been completely replaced by Earth minerals except for resistant chromite grains. A few paleometeorites, such as Lake Murray, an iron found in Oklahoma, are thought to have been buried in sediments for more than 100 million years.
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