A new study that has made its way in the news suggests a significant shift in our understanding of the world’s geological history. This study proclaims that the earliest continental landmass emerged around 3.2 billion years ago, defying the previous idea of it forming 2.5 billion years ago according to the Continental Drift Theory. This groundbreaking research was conducted by an international team of researchers from India, Australia, and the US.
The Continental Drift Theory
Proposed by German meteorologist Alfred Wegener in 1912, the Continental Drift Theory explains the distribution of continents and oceans. According to the theory, at one point, all continents composed a single large landmass known as Pangea, encircled by a mega ocean referred to as Panthalassa. Approximately 200 million years ago, Pangea began splitting into two principal continental masses – Laurasia and Gondwanaland, representing the northern and southern components respectively. Afterwards, these masses further disintegrated into smaller continents that make up today’s world map.
Key Points About the New Study
The recent study disrupts the conventional notion that continents arose from the oceans around 2.5 billion years ago. Instead, it propounds that this event took place approximately 700 million years earlier than estimated, around 3.2 billion years ago. The oldest continental landmass to surface might have been in Singhbhum region of Jharkhand, India. Other regions where patches of the earliest continental land have been found include Australia and South Africa. Due to geological resemblances, the Singhbhum craton has been tied to similar structures in South Africa and Western Australia.
Major Findings of the Study
Noteworthy findings of the research include the discovery of river channels, tidal plains, and beaches in ancient sedimentary rocks, particularly sandstones. Assessment of uranium and lead components revealed these rocks to be 3.1 billion years old, suggesting that they were formed in ancient rivers, beaches, and shallow seas. These bodies of water could only have existed if there was continental land, inferring that the Singhbhum region was above the ocean before 3.1 billion years ago.
Extensive Volcanism
The researchers also scrutinized the granites forming the continental crust of Singhbhum region that ranges from 3.5 to 3.1 billion years old. They concluded that extensive volcanism led to the formation of these granites, happening deep inside Earth and continuing intermittently for hundreds of millions of years until all the magma solidified to form a thick continental crust in that area.
Evolution of Organisms
The theory also claims that early emergence of continents might have aided the spread of photosynthetic organisms, leading to increased oxygen levels in the atmosphere. Weathering of the cratons would have resulted in nutrient runoff, supplying phosphorus and other essential elements to the ocean, enriching it for early life.
Significance of the Study
As the world contemplates climate change, understanding the origins of our atmosphere, oceans, and climate and their interaction with geological processes deep within Earth becomes critical for comprehending our planet’s panorama. This study provides an opportunity to connect Earth’s interior to its exterior over eons. With India boasting three other ancient continental fragments—Dharwar, Bastar, and Bundelkhand—this research serves as a robust template for studying these other cratons too.
