Zealandia: Earth’s Forgotten eighth continent

An international team of geologists and seismologists have now created a new map of Zealandia

By DTE Staff
Published: Monday 02 October 2023

Zealandia is Earth’s forgotten and submerged eighth continent. Scientists had long predicted the existence of this bonus southern landmass that remained missing for 375 years, largely because it’s submerged 1-2 kilometres under water. An international team of geologists and seismologists have now created a new map of Zealandia.

Approximately 83 million years ago, the supercontinent Gondwana was pulled apart resulting in the beginning of the present-day continents. It also resulted in the creation of Zealandia. It is 94 per cent under the sea and the remaining six per cent is what we identify as New Zealand and neighboring islands.

In a new effort, the research team sought to refine the existing maps of Zealandia by studying a collection of rocks and sediment samples brought up from the ocean bed.

The oldest were the pebbles dating back to Early Cretaceous (around 130-110 million years old), followed by sandstones from Late Cretaceous (around 95 million years old) and relatively young basalts from the Eocene (around 40 million years old).

Study of rock patterns showed geologic patterns in West Antarctica that hinted at the possibility of a subduction zone near the Campbell Plateau off the west coast of New Zealand. The newly refined map shows other major geological features as well.

A 2021 study suggested that Zealandia is one billion years old, about twice as old as geologists previously thought. By approximately 23 million years ago, the landmass may have completely submerged.

Zealandia is also substantially larger than the Arabian Peninsula, the world’s largest peninsula, and the Indian subcontinent. Due to various geological considerations, such as crustal thickness and density, some geologists from New Zealand and Australia have concluded that Zealandia fulfills all the requirements to be considered as a continent rather than a microcontinent.

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