Earth’s first landmass emerged in Singhbhum

Subject – Geography

Context – Earth’s first landmass emerged in Singhbhum: study

Concept –

A new study has challenged the widely accepted view that the continents rose from the oceans about 2.5 billion years ago. It suggests this happened 700 million years earlier — about 3.2 billion years ago — and that the earliest continental landmass to emerge may have been Jharkhand’s Singhbhum region.
Scientists have found sandstones in Singhbhum with geological signatures of ancient river channels, tidal plains and beaches over 3.2 billion years old, representing the earliest crust exposed to air.
Patches of the earliest continental land, however, exist in Australia and South Africa, too.
These granitesthat formed the continental crust of Singhbhum region are 3.5 to 3.1 billion years old and formed through extensive volcanism that happened about 35-45 km deep inside the Earth and continued on-and-off for hundreds of millions of years until all the magma solidified to form a thick continental crust in the area.
- Due to the thickness and less density, the continental crust emerged above surrounding oceanic crust owing to buoyancy.
The researchers believe the earliest emergence of continents would have contributed to a proliferation of photosynthetic organisms, which would have increased oxygen levels in the atmosphere.