Zealandia : An international team of geologists and seismologists created a newly refined map of Zealandia – considered the “eighth continent of the world” and located under the Pacific Ocean – using data from rock samples scraped from the seabed.
Their study of Zelandia, a 1.89 million square kilometre (4.9 million square miles) land mass about six times the size of Madagascar, was recently published in the journal Tectonics.
Previous studies show that approximately 83 million years ago, geological forces broke apart the supercontinent Gondwana, resulting in the formation of the continents that exist today – Asia, Africa, Europe, North and South America, Australia/Oceania, and Antarctica. This also led to the birth of New Zealand, of which 94% is believed to be under the sea – the remaining 6% being New Zealand and its surrounding islands.
In this new project, the research team sought to improve existing maps of Zealandia by examining collections of rock and sediment samples lifted from the ocean floor. The team then examined the samples as part of a secondary study that included analysis of seismic data from the area. They then created a complex map of the entire continent of Zealandia.
Examination of rock samples revealed geological patterns in West Antarctica that suggested the possibility of a subduction zone near the Campbell Plateau on the west coast of New Zealand. The newly improved map shows not only the location of the magma arc axis of the Zeeland continent, but also other important geological features.
An earlier study in 2021 showed Zealandia to be a billion years old, about twice as old as geologists had previously thought. About 23 million years ago, the Earth may have been completely underwater.
Zealandia has a total area of about 4,900,000 square kilometres, which is significantly larger than any of the features known as microcontinents and continental shelves. If Zealand were classified as a microcontinent, it would be the largest microcontinent in the world. Its area is six times the area of Madagascar, the second largest microcontinent in the world, and more than half the area of the Australian continent.
Zealand is also significantly larger than Arabia (3,237,500 km2 or 1,250,000 sq mi), the world’s largest peninsula, and the Indian Peninsula (4,300,000 km2 or 1,700,000 sq mi). Because of these geological aspects, such as the thickness and density of the earth’s crust, some geologists in New Zealand and Australia have concluded that New Zealand meets all the requirements to be considered a continent rather than a microcontinent.