Study on meteorite provides clues to Earth's mantle

The meteorite originated in the asteroid belt, was sucked in by Earth’s gravity

On November 13, 2015, a meteorite fell near the town of Kamargaon in Assam, India. It weighed a little over 12 kg and scientists decoded its mineral composition and classified it as a chondrite, a variety of stony meteorite. A new study has now shown that by studying this meteorite and its minerals we may find new clues about the Earth’s lower mantle. “We are always interested in knowing how this planet of ours was formed. The Earth has different layers - the upper, very thin crust, followed by the intermediate silicate mantle which starts from 30 km to 2,900 km depth, and then the centre iron-nickel alloy core. The mantle faces high temperature and pressure. So by studying these meteorites which may have experienced similar high pressure and temperature conditions, we can understand the inaccessible mantle layer in detail,” explains Sujoy Ghosh from the Department of Geology and Geophysics at the Indian Institute of Technology, Kharagpur. He is one of the authors of the paper recently published in Geophysical Research Letters. Previous studies had noted that the Kamargaon meteorite contains minerals such as olivine, pyroxene, plagioclase and chromite. Olivine is also found in Earth's upper mantle. It is known to break down into bridgmanite and magnesiowustite in Earth’s lower mantle conditions. This breaking down is an important reaction that controls the physical and chemical properties of the Earth's interior.