Indian meteorite that helped study Earth’s formation
- October 11, 2021
- Posted by: OptimizeIAS Team
- Category: DPN Topics
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Indian meteorite that helped study Earth’s formation
Subject – Science and Tech
Context – On May 22, 2012, a large meteor shower occurred near the town of Katol in Nagpur.
Concept –
- On May 22, 2012, a large meteor shower occurred near the town of Katol in Nagpur. The next day, researchers from the Geological Survey of India collected about 30 meteorite fragments with the largest weighing around a kilogram.
- Initial studies revealed that the host rock was mainly composed of olivine, an olive-green mineral.
- Olivine is the most abundant phase in our Earth’s upper mantle.
- Our Earth is composed of different layers including the outer crust, followed by the mantle and then the inner core.
- You can reach the upper mantle if you drill for about 410 kilometers.
- Now, by studying the composition of these meteorite fragments, researchers have unravelled the composition expected to be present in the Earth’s lower mantle which is at about 660 km deep.
How to study a meteorite?
- The researchers took a small sample of the meteorite and examined it using special microscopy techniques.
- The mineralogy was determined using a laser micro-Raman spectrometer.
- These techniques helped the team identify, characterize the crystal structure of the meteorite and determine its chemical composition and texture.
What does the new study show?
- The paper published this month in PNAS reports the first natural occurrence of a mineral called bridgmanite.
- The mineral was named in 2014 after Prof. Percy W. Bridgman, recipient of the 1946 Nobel Prize in Physics.
- Various computational and experimental studies have shown that about 80% of the Earth’s lower mantle is made up of bridgmanite.
- The bridgmanite in the meteorite was found to be formed at pressures of about 23 to 25 gigapascals generated by the shock event.
- The high temperature and pressure in our Earth’s interior have changed over billions of years causing crystallisation, melting, remelting of the different minerals before they reached their current state.
Evolution of Earth
- The inner planets or terrestrial planets or rocky planets Mercury, Venus, Earth, and Mars are formed by accretion or by rocky pieces coming together and forming a planet by increased pressure and high temperature caused by radioactive elements and gravitational forces.
- Our Earth was an ocean of magma before the elements crystallised and stabilised and the different layers such as core, mantle were formed. The heavier elements like iron went to the core while the lighter silicates stayed in the mantle.