Clues from meteorites to Earth’s mantle.

#GS3 #SCIENCE AND TECHNOLOGY #METEORITE STUDY 

Recently in news:

An analysis of a meteorite that fell near the town of Kamargaon in Assam, India on November 13, 2015.

Background:

  • Previous studies had noted that the Kamargaon meteorite contains minerals like olivine, pyroxene, plagioclase and chromite.  
  • Olivine is additionally found in Earth's layer .  
  • It breaks down into bridgmanite and magnesiowustite in Earth’s lower mantle conditions.  
  • This breaking down is a very important reaction that controls the physical and chemical properties of the Earth's interior.

Major finidngs out of the research:

  • It weighed a bit over 12 kg and scientists decoded its mineral composition and classified it as a chondrite, a spread 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 layer .

Layers of the Earth:

  • 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.  
  • According to the Department of Geology and Geophysics at the Indian Institute of Technology, Kharagpur;  
  • By studying these meteorites which can have experienced similar high pressure and temperature conditions, we will understand the inaccessible mantle layer thoroughly.

Olivine dissociation:

  • Using new high-resolution microscopy and spectroscopy, researchers studied this dissociation reaction of olivine within the Kamargaon meteorite.
  • They noted an alternate mechanism and reactions which will be driving the transformation of olivine.
  • It is possible that when materials are transported to the lower mantle by convection or subduction, there would be high-temperature conditions within the lower mantle that might cause this dissociated reaction.
  • The results suggest what processes and reactions could also be involved in the formation of Earth’s layer .

Sucked by gravity:

  • This meteorite originated from the asteroid belt, between Mars and Jupiter, and was somehow sucked by Earth’s gravity.  
  • By studying different meteorites, we will understand in detail about their parent body and in the process understand our own planet and its formation.  

BIASA BASICS 

Meteorites:

  • They are objects in space that range in size from dust grains to small asteroids. consider them as “space rocks."
  • When meteoroids enter Earth’s atmosphere (or that of another planet, like Mars) at high speed and deplete, the fireballs or “shooting stars” are called meteors.
  • When a meteoroid survives a visit through the atmosphere and hits the ground, it’s called a meteorite.
Make Your Own Edible Meteorites - The National Space Centre

Asteroids:

  • Asteroids, sometimes called minor planets, are rocky, airless remnants left over from the early formation of our solar system about 4.6 billion years ago.
  • The current (as of June 2021) known asteroid count is: 1,096,765.
  • Most of this ancient space rubble are often found orbiting the Sun between Mars and Jupiter within the most belt .
  • Asteroids range in size from Vesta (the largest at about 329 miles (530 kilometres) in diameter) to bodies that are but 33 feet (10 meters) across.
  • The total mass of all the asteroids combined is a smaller amount than that of Earth's Moon.
List of exceptional asteroids - Wikipedia

 

SOURCE: THE HINDU 

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