Bridgmanite

Bridgmanite

Subject – Geography

Context – Scientists find a mineral seen in the depths ofthe Earth in a meteorite

Concept –

• The key findings of a study led by IIT Kharagpur researchers could help us understand the formation and evolution of the Earth.
  • They have studied a meteorite that fell near the town of Katol in Nagpur District of Maharashtra on May 22, 2012, reporting for the first time, presence of veins of the mineral bridgmanite, which is the most abundant mineral in the interior of the Earth, within the Katol L6 Chondrite meteorite.
  • This finding adds evidence to the Moon-forming giant impact hypothesis.
• Bridgmanite is the most volumetrically abundant mineral of the Earth’s interior.
  • It is present in the lower mantle (from 660 to 2700 km).
  • Bridgmanite consists of magnesium, iron, calcium aluminum oxide and has a perovskite structure.
  • While the crystal structure of natural bridgmanite has been reported in other meteorites such as the Tenham and Suizhou meteorites, their chemical composition does not fully match with the terrestrial bridgmanite present in the Earth’s interior between 660 and 2700 km depth
• The Moon-forming giant impact hypothesis is that long ago, nearly 4.5 billion years ago, the Earth collided with a planet the size of Mars named Thela, and the force of this impact was so huge as to melt the Earth down from the surface to a depth of 750 km to 1,100 km.
  • The hypothesis goes that this caused the Earth to be bathed in a magma ocean, and the ejecta from the collision led to the formation of the Moon.
  • This is the most favoured hypothesis on the formation of the Moon and the present finding by the Kharagpur team lends further support to it.
• Earth was an ocean of magma in the past. The heavier iron and nickel went to the core while the lighter silicates stayed in the mantle. By studying the meteorite, we can understand more details about the formation of the Earth and other planets.