Prelims – Current events of national and international importance| World Geography.
Mains (GS I) – Geographical features and their location-changes in critical geographical features (including water-bodies and ice-caps) and in flora and fauna and the effects of such changes.
Why in News?
New research suggests that Earth’s first crust, formed over 4.5 billion years ago.
- The Hadean protocrust is the name for the earth’s crust, its outermost layer when it first formed.
- Hadean Aeon - The term 'Hadean' denotes the initial geologic aeon of the planet.
- Conditions of Earth - During this period, approximately 200 million years after its formation, the Earth's surface was partially in a molten state and was frequently struck by extraterrestrial rocks.
- The surface was extremely hot and hellish, as numerous volcanoes erupted simultaneously.
- Formation of Crust - As the magma ocean began to cool, the initial fragments of the crust started to form.
- However, it remained somewhat unstable, with certain sections breaking away while new areas solidified.
- Plate Tectonics - The thicker parts of the crust slowly formed the first continents, which moved like plates on the asthenospheric mantle, a layer of hot, gooey rock going 400 km down.
- These plates began to converge, occasionally sliding past one another or submerging beneath each other.
- Over thousands of years, these tectonic movements have imprinted distinctive chemical signatures in the crust.
- Indeed, researchers have been able to trace the history of plate tectonics by examining these signatures.
Reference
The Hindu | What is the Hadean protocrust?
