Part Of Ancient Billion-Year-Old Subcontinent Found Under New Zealand

Part Of Ancient Billion-Year-Old Subcontinent Found Under New Zealand

A team of geologists have discovered a billion-year-old supercontinent hiding underneath New Zealand.

Source: Lad Bible

After decades of research, scientists have been able to confirm the existence of mysterious eighth continent Zealandia, also known by its Māori name Te Riu-a-Māui.

The chunk of land is located beneath the eastern side of New Zealand’s South and Stewart Islands.

Credit: GNS Science
Credit: GNS Science

So how have boffins been able to confirm its existence? To explore that, we’ll have to go back a few years.

In 2018, geologist Rose Turnbull was in a colleague’s lab at California State University and was sorting through small grains of sand, looking for tiny crystals of a mineral called zircon that would help unlock some much-sought information about Zealandia.

The study involved crushing down 169 samples of rock and sorting the grains in order of density and magnetics, until all that remained was fine sand and zircon crystals. Turnbull was able to pick out thousands of zircons from the samples, in what she referred to as a ‘full-on process’.

The crystals were extracted from rocks originating from the islands of New Zealand – despite Zealandia occupying a region of nearly two million square miles, these rocks are among very few parts that are visible above sea level.

As described in a study published by the Geology journal, continents usually contain a core of rock known as craton, which is basically a billion-year-old ‘geologic nucleus’ where continents are built upon.

In other words – no craton, no party.

Until now, the oldest continental crust found on Zealandia was dated back to 500 million years ago – not very old in geologic terms, it seems.

However, it is now known that Zealandia consists of older rocks, including bits of the mantle as old as 2.7 billion years. However, more ancient crust has been elusive.

This newfound fragment of ancient rock may be part of the missing piece for Zealandia. The discovery ‘ticks the final box’, according to Turnbull. She told National Geographic: “We are sitting on a continent.”

Credit: PA
Credit: PA

One of the authors of the study, Joshua Schwartz, is a geologist specialising in granites at California State University.

He went into more detail, telling National Geographic: “That layer on top of the Earth that we call the crust, that thin layer is where all the action for life happens.

“The continental crust is where we live, grow crops, draw water, mine minerals, and more.

“Essentially, all of our life is built on crust.”

Zealandia is still considered a younger sibling to the other continents because the rocks are much less old than all the other major continents, which are said to host rocks dating back to more than three billion years ago.

Source: Lad Bible

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