Hadean protocrust

Hadean protocrust: A recent study led by Macquarie University in Australia challenges a key geological assumption, suggesting that chemical signatures previously linked to plate tectonics may have existed in the Hadean protocrust, before the onset of plate subduction.

• About: The Hadean protocrust is the name for the earth’s crust — its outermost layer — when it first formed.
• Hadean Aeon: The ‘Hadean’ prefix refers to the planet’s first geologic aeon.
• Early Earth Conditions: Within 200 million years of its genesis, the earth’s surface was partially molten and almost constantly bombarded by rocks from space.

  o Many volcanoes raged, making the surface very hot and hellish.

  • Formation of Crust: As parts of the magma ocean cooled, the first pieces of the crust began to take shape.

  o The crust was somewhat flaky, with parts sloughing off and new parts solidifying.

  o 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.

  • Plate Tectonics: Plates began drifting into each other, sometimes sliding over or diving under.

  o Such plate tectonics have left unique chemical signatures in the crust over millennia.

  o Scientists have understood history of plate tectonics by studying these chemical signatures.

  • New Study's Findings: The researchers reported that the signatures associated with plate tectonics actually existed in the Hadean protocrust, before the plates began to subduct.