Singhbhum : One of the Earliest Lands on the Earth!

Manoj Pandey*

There are many theories on how oceans and continents originated on the earth. These theories have some valid arguments and geological proofs behind them, but there is no consensus on many of them. However, one interesting happening about which most geologists agree, is a series of development over millions of years in which continents were created, and they moved across the earth, joined together and broke apart. 

Let us talk about the Indian subcontinent. Recall this bit about plate tectonics from your school text books:  The earth crust is made up of huge continental plates, and a plate that makes today’s India, and surrounding countries has been pushing itself under the Eurasian plate. This has made the Indian subcontinent a part of the Asian continent and given rise to the great Himalayas. So, they say, Aravalis and other southern mountain ranges are much older than the Himalayas.

A mineral-rich region in the eastern part of India is the most ancient part of the subcontinent. And, believe it, this region - Singhbhum - travelled thousands of miles from far north of the globe and gathered land mass around it to give rise to today’s continents. 

The Singhbhum craton (Craton is the stable part of a continental plate) covers a large area of Jharkhand and parts of adjoining states. 

Let’s go on time travel to check how this all might have happened. 

It is about 4 billion years ago. The earth surface has received a great amount of free water that was earlier bound in its minerals. Recently (in geological timescale) the earth had also been punched by a huge planetary object, and this object is also supposed to have brought water with it. By the way, the impact of this large body also created the moon by flinging a part of the earth into space. Icy objects in the solar system, which have been getting attracted to the earth, have also brought in a good quantity of water. As cooling occurs, earth surface gets covered with water.

A billion years forward. A continent starts emerging. This is nothing but a large mass of earth’s crust, part of which rises over the surrounding water. Geologists call it Ur. Since there are no continents, there is only one ocean.

Another half-a-billion forward; it is 2.5 billion ago from today. Another continent arises, which will be joined by yet another one in half a billion years later. 

One billion years ago. These continents grow bigger, as more of earth’s crust solidifies and rises around them. Because of movements in the molten core of the earth and also tectonics (movement of earth’s crust in the form of plates, which glide over the inner core), these continents converge into a continent, Rodinia. 

The continents again separate and then converge some 300 million years ago. This gives rise to a supercontinent, Pangea.

The most accepted geological theory - though there is no meeting ground about the time-scale - is that around 200 million years ago, Pangea broke and its parts started moving away from one another. Some parts broke up further, and merged with others, giving rise to the continents as they are today.

What makes India an interesting story, and Singhbhum even more so, is that till about 40-50 million years ago, there were no Himalayas. A part of the supercontinent broke when other parts had moved away, and then it moved north at a rather fast speed (5-6 cm a year). This plate (carrying most of the modern-day India) pushed (and is still pushing) itself under the Eurasian plate that carries Tibet and China on it. As it moved beneath the bigger plate, tectonic and volcanic activities gave rise to the Himalayas. The fractions of Ur, the oldest continent, are believed to be now distributed in the eastern part of Africa, Madagascar, Singhbhum and the western part of Australia. 

Geologists studying Singhbhum have found oceanic sand 3.2 billion years old. At that time, the earth was too hot, though cool enough to allow water vapour to turn into water. Volcanic activities brought molten minerals from the inside of the earth to the surface, water cooled the molten magma to create layers of crust. It was only in places where this deposition became very thick (nearly 50 km) and subsequent volcanic activities did not submerge it into water, new land started emerging out of the huge ocean.  

Scientists who have studied the minerals at Singhbhum in detail have proposed the findings as a proof that creation of continents began over 3.2 billion years ago, as against an earlier consensus of 2.5 billion years ago. 

Thus, before Singhbhum (perhaps a part of the earliest continent) became part of today’s India, it seems to have merged into and broken apart from other continents a number of times. By the way, India is supposed to be the biggest repository of segments of Ur continent, in the form of Aravali, Dharwar and Bundelkhand cratons, besides the Singhbhum craton. 

A truly rich geology of a land that happens to be one of the most mineral-rich regions of India!

Further reading

• Earth’s first landmass emerged in Singhbhum: study
• In the beginning, there was Ur
• Magmatic thickening of crust in non–plate tectonic settings initiated the subaerial rise of Earth’s first continents 3.3 to 3.2 billion years ago
• Pangea
• Ur (continent)

*Manoj Pandey is a former civil servant. He does not like to call himself a rationalist, but insists on scrutiny of apparent myths as well as what are supposed to be immutable scientific facts. He maintains a personal blog, Th_ink

Disclaimer: The views expressed in this article are the personal opinion of the author and do not reflect the views of raagdelhi.com which does not assume any responsibility for the same.