Hadean protocrust

News: A new study by an international team of researchers led by Macquarie University in Australia has called the assumptions around plate tectonics theory into question in light of existence of Hadean protocrust. Hadean protocrust.

About Hadean protocrust

• It is the name for the outermost layer of earth’s crust, when it first formed in first geologic aeon (around 4 – 4.6 billion years ago).
• The ‘Hadean’ prefix refers to the planet’s first geologic aeon.
• The eon’s name “Hadean” comes from Hades, the Greek god of the ‘underworld’.

Geological procedures during Hadean aeon

• Within 200 million years of its genesis, the earth’s surface was partially molten and constantly bombarded by rocks from space. The surface was very hot and hellish due to erupting volcanoes.
• With time, parts of the magma ocean started to cool down and the first pieces of the crust began to take shape.
• Formation of plates: The thicker parts of the crust slowly formed the first continents, which moved like plates on the asthenospheric mantle, a layer going 400 km down.
• Plate actions and their signatures: The plates soon began drifting into each other – sliding over or diving under each other, leaving unique chemical signatures in the crust over millennia.
• These chemical signatures have been most important in understanding the history of plate tectonics by studying them.

The new study

• Now a new study has reported that the chemical signatures that scientists have associated with plate tectonics, actually existed in the Hadean protocrust, before the plates even began to subduct. So, it suggests that the continental crust began forming earlier than previously thought.