Earth's First Continent Emerged in India 700 Million Years Earlier than We Thought

We are always wondering how the Earth originated and want to know how it has developed. Geoscientists are constantly investigating and giving information about it. Recently scientists have said that the first continent on the Earth has come out of the land of India. Herewith, this fact has also revealed the doubt about the origin of the first continent of the Earth. According to the report published in 'The Guardian', the first continent of the Earth is called Cratons. The Cratons had come out of the sea 2.5 billion years ago. According to this new study, the first contest of the Earth was made at least 700m years earlier than previously thought and the process was started 3.2 billion years ago. This investigation was undertaken by geologist Dr. Priyadarshi Chowdhury and his colleagues work at Australia's Monash University. 

The rocks in this image are part of the Singhbhum Craton in India, which emerged from the ocean more than 3 billion years ago. Photograph: Subham Mukherjee / University of Delhi

This new study has been published in the Proceedings of the National Academy of Sciences (PNAs). Singhbhum Cratons was the part of the world's first continent which is located in the eastern part of India. At the same time, after examining scientists said that some geological signatures of Ancient River channels, tidal plains, and beaches over 3.2 billion years old have been identified, representing the earliest crust exposed to the atmosphere. 

“We found a particular type of sedimentary rocks, called sandstones. We then tried to find their age and in which conditions they have formed. We found the age by analyzing the uranium and lead contents of tiny minerals. These rocks are 3.1 billion years old and were formed in ancient rivers, beaches, and shallow seas. All these water bodies could have only existed if there was continental land. Thus, we inferred that the Singhbhum region was above the ocean before 3.1 billion years ago,” Chowdhury said.

 

Researchers from Monash University studied the sedimentary and igneous rocks of an ancient continental fragment in India called the Singhbhum Craton (Image: Mail Online)

Scientists also told that the Cratons were tolerating the impact of air and water due to their unique rock layer. Scientists have been surprised by their study by searching Zircons small crystals within this. The scientists were trying to understand the forces and process behind the surprising fact that Singhbhum Cratons came out of the sea. By laser technique analysis at the zircon, scientists can measure the relative amounts of elements released and the team was able to estimate the age of the rocks by this method. 

Sandstone horizons that are 3.1 billion years old and formed atop the crust of the Singhbhum Craton in India soon after its emersion (Photo: Subhajit Roy)

According to the report of “The Indian Express,” Dr. Priyadarshi Chowdhury answered the question “when the first landmasses were formed lay in the sedimentary rocks of the region? “We found a particular type of sedimentary rocks, called sandstones. We then tried to find their age and in which conditions they have formed. We found the age by analyzing the uranium and lead contents of tiny minerals. These rocks are 3.1 billion years old and were formed in ancient rivers, beaches, and shallow seas. All these water bodies could have only existed if there was continental land. Thus, we inferred that the Singhbhum region was above the ocean before 3.1 billion years ago,” Chowdhury said. 

ANALYSIS OF THE ORIGIN

The researchers studied the granites that structured the continental crust of the Singhbhum region of eastern India. “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. Due to the thickness and less density, the continental crust emerged above surrounding oceanic crust owing to buoyancy,” Chowdhury stated. 

Dr. Chowdhury revealed that the Singhbhum Cratons may have been formed from a pile-up of lava over time so that the crust about 50km deep – “becomes so thick and it just floats up above the water just like an iceberg floating on water”. This research identified the geological similarities among Singhbhum Cratons to Cratons in South Africa and Western Australia. The scientists think weathering of the Cratons would have led to nutrient surplus, supplying the ocean with phosphorus and other building blocks for early life.

References: The Guardian, InsideScience, Daily Mail, The Indian Express, The Times of India, Independent