Earth’s first landmass emerged in Singhbhum

In news– A new study has suggested that the earliest continental landmass emerged from Jharkhand’s Singhbhum region.

Key highlights of the study–

Researchers 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.
They have found the age by analysing the uranium and lead contents of tiny minerals and studied the granites that form the continental crust of Singhbhum region.
According to them, these granites 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.
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.
This study was conducted by researchers from India, Australia and the US.
The researchers also aim to understand the evolution of India’s three other ancient continental fragments — Dharwar, Bastar and Bundelkhand regions.

Theories of landmass evolution–

Continental Drift theory- It is the hypothesis that the Earth’s continents have moved over geologic time relative to each other, thus appearing to have “drifted” across the ocean bed. It is associated with Alfred Wegener.
Convectional Current theory- According to this theory, the intense heat generated by radioactive substances in the mantle seeks a path to escape, giving rise to the formation of convection currents in the mantle. It was proposed by Arthur Holmes in the 1930s.
Seafloor spreading theory- This theory, introduced by Harry Hess & Robert Dietz, was proven as patterns of magnetic field polarity preserved in seafloor basalt and by age dating of the rocks.Polar wandering theory- This theory is similar to Continental Drift theory. It is the relative movement of the earth’s crust and upper mantle with respect to the rotational poles of the earth.