Unearthing Zealandia

• Zealandia, also referred to as Riu-a-Māui in the Māori language, is a vast expanse of partially submerged continental fragments, spanning about 1.89 million square miles.
• The existence of Zealandia was confirmed after 375 years of exploration and speculation.
• Scientists believe that Zealandia was once a part of the supercontinent Gondwana, which also included regions such as Australia and Antarctica, around 500 million years ago.
• Zealandia began to detach from Gondwana in the Late Cretaceous as a ribbon continent stretching 4000-km-long, for reasons that remain unclear.
• It gradually sank beneath the ocean surface as it continued to drift away from Gondwana.
• Currently, over 94% of Zealandia remains submerged, at a depth of around 6,560 feet under the water.
• The first recorded mention of Zealandia was made by Dutch businessman and sailor Abel Tasman in 1642, during his quest to discover the Terra Australis or the “Great Southern Continent”.
• Despite his efforts, Tasman failed to locate this new land.
• The local Māori provided essential information about the surrounding landmass, hinting at the existence of a large landmass towards the east.
• However, it took nearly four centuries for the scientific community to acknowledge the existence of Zealandia.
• Finally, in 2017, GNS geologists confirmed the existence of Zealandia.

Significance of the Discovery:

• Zealandia constituted approximately 5% of the area of Gondwana.
• Studying Zealandia can provide insights into the geological history of the Mesozoic convergent margin of southeast Gondwana.
• Without Zealandia, our understanding of the Paleozoic-Mesozoic geology of Gondwana, eastern Australia, and West Antarctica would be incomplete and potentially misleading.
• The critical role of Zealandia has not been considered in comparative studies of continental rifting, leading to a potential knowledge gap in our understanding of continental structure and formation.
• By examining Zealandia, we can learn more about the cohesion, rheology, and extensional deformation of continental crust and lithosphere.
• Zealandia is the youngest, thinnest, and most submerged continent on the planet.
• The classification of Zealandia as a continent has scientific implications far beyond simply adding another name to the list.
• Despite its submerged geography, Zealandia remained unfragmented, making it a valuable and intriguing case study in exploring the cohesion and breakup of continental crust.