Experts have studied the ancient deposits of continental rocks, which were previously found in the territory of modern India.

Understanding when and how subaerial continental crust originated is vital since it is considered to have played a key role in establishing Earth’s habitability.

Despite debates, the general view is that plate tectonics drove the subaerial rise of continents 2.5 billion years ago.

According to a new study published in the journal Proceedings of the National Academy of Sciences, Geologists found that India’s Singhbhum region may have been the first continental land to rise above the ocean 3.2 billion years ago, pushing back the creation of continents by 700 million years.

Plate tectonics, which involves the horizontal movement, collisions, and upward movement of continental plates, was thought to have formed the continents roughly 2.5 billion years ago, according to geologists.

The latest data, on the other hand, show that the Earth’s oldest continents arose from huge eruptions of magma that consolidated into continental crust starting 3.5 to 3.2 billion years ago, rather than plate tectonic processes.

“The Singhbhum region is possibly Earth’s earliest continental land exposed to the air,” said the lead study author Priyadarshi Chowdhury from Australia’s Monash University.

“Before that, Earth was a water world, the whole planet covered by water.”

However, pockets of the earliest continental land can be found in Australia and South Africa, according to Chowdhury.

The Singhbhum craton — a huge swath of rocky territory that runs mostly through parts of Jharkhand and Odisha, between the Chhota Nagpur plateau and the Eastern Ghats — features some of the world’s oldest rocks, as geologists have known for decades.

Chowdhury and his colleagues looked at river channels, tidal zones, and beaches in Singhbhum’s 3.2-billion-year-old sandstones and found traces of river channels, tidal zones, and beaches — all of which occur on crust exposed to the air, not crust underwater.

“This is the most direct, unambiguous date yet for the emergence of continental land,” Chowdhury added.

According to the team’s research, Singhbhum’s elevation climbed during a 300-million-year span, rising from 3.6 kilometers below sea level 3.5 billion years ago to nearly 1.8 kilometers above sea level 3.2 billion years ago.

While today’s elevated landmasses, such as the Himalayas, are the result of two tectonic plates colliding, a new study suggests that the earliest continents rose above sea level due to the gradual infusion of magma from deep within the Earth.

“Sections of granite in the Singhbhum region have telltale chemical signatures that point to their magmatic origin,” added Subham Mukherjee – one of the study authors and a geologist at Delhi University.

The study, according to Chowdhury, looked into two aspects of the emergence of continents: when and how.

“The sandstones tell us when and the granite tells us how,” he said.

The research suggests that the early appearance of continents aided the proliferation of photosynthetic species, resulting in a rise in atmospheric oxygen levels.

The formation of continental land would have resulted in shallow oceans, which are great settings for cyanobacteria to thrive.

“Early continental masses created habitats where early cyanobacterial life boomed. Cyanobacteria are photosynthetic,” Chowdhury added. “They produced free oxygen we’re breathing today.”

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