Kathmandu, Oct 9: In 1820, a Russian ship sailing in the Southern Ocean spotted a massive icy shoreline, marking the discovery of Antarctica. This event solidified the idea of seven continents, including Europe, Asia, Africa, North America, South America, Australia, and Antarctica. However, in 2017, scientists made a groundbreaking discovery – Zealandia, an underwater continent southeast of Australia, was revealed as Earth’s eighth continent.

Zealandia’s formation began about 83 million years ago, during the time of the dinosaurs, as the supercontinent Gondwana started to break apart. Zealandia eventually separated from Gondwana and became its continent, but it sank beneath the ocean’s surface around 25 million years ago, making it nearly invisible.

Researchers used bathymetry (the study of water depths) to analyze Zealandia’s shallow ocean floor, indicating that it wasn’t an ordinary oceanic plate but a continental one. They also examined the continent’s rocks and thickness, leading to the conclusion that Zealandia is indeed a continent, with 95% submerged underwater.

Zealandia’s history has been challenging to unravel due to its unique stretching and twisting during its separation. It stretched in two phases, forming the Tasman Sea and then splitting from West Antarctica to create the Pacific Ocean.

In recent studies, scientists explored North Zealandia, examining ancient rocks dredged from the Fairway Ridge. These rocks dated back to the time when Zealandia was above water, with the oldest rocks around 130-110 million years old. Magnetic anomalies in the ocean floor also revealed how Zealandia stretched over millions of years, resulting in its thinning and eventual sinking.

Zealandia’s secrets are slowly being unveiled, but with most of it underwater, uncovering its mysteries will take time.