KOMPAS.com – According to maps and encyclopedias, there are seven large plains (continents) on the Earth’s surface.
However, in 2017, a group of geologists announced their discovery of an eighth continent which became known as Zealandia or Te Riu-a-Maui in Maori.
The continent has an area of 1.89 million square miles (4.9 million square km). It is about six times the size of Madagascar.
One of the famous countries located on this continent is New Zealand.
The continent of Zealandia is hidden underwater
It is not easy to claim that the Zealandia Continent is the eighth continent on Earth.
Because, 94 percent of this continent is below sea level. Only a handful of islands, like New Zealand, rise from the depths of the ocean.
“This is an example of how something so obvious can take quite a long time to be revealed,” said Andy Tulloch, a geologist at the Crown Research Institute GNS Science, quoted by the BBC.
The first clues to the continent of Zealandia were collected by Scottish naturalist Sir James Hector, who sailed off the southern coast of New Zealand in 1895.
The voyage was carried out a century after the island of New Zealand was discovered, in 1642 to be precise.
After studying its geology, he concluded that New Zealand was the remains of a chain of mountains that formed the crest of a large continental region that stretched far to the south and east, but was now sinking.
Geologists have finally agreed on a definition of what a continent is.
In general, a continent is a geological area with height, various types of rocks, and a thick earth’s crust. Continents must also be large.
However, the mission to discover the Zealandia Continent was stopped due to a complicated and expensive expedition
In 1995, American geophysicist Bruce Luyendyk again described the region as a continent and suggested calling it Zealandia.
Also read: Nicknames for the 7 Continents in the World and the Reasons
Zealandia Continent Controversy
Even though it is thin and sinking, geologists say Zealandia is a continent because of the types of rocks found in the area.
Continental crust tends to consist of igneous, metamorphic, and sedimentary rocks such as granite, schist, and limestone. Meanwhile, the ocean floor is usually only made of igneous rocks such as basalt.
However, there are still many things that are not known about this continent, one of which is the continent’s origins.
Some scientists even disagree if this sunken land is called the eighth continent.
“It’s not like a mountain, a country or a planet. There is no official body that approves a continent,” said Nick Mortimer, a geologist from GNS Science New Zealand who led the 2017 group, as reported by Insider.
Mortimer’s group said that a continent must have well-defined boundaries, occupy an area greater than 386,000 square miles (1 million square kilometers), be higher than the surrounding oceanic crust, and have continental crust that is thicker than oceanic crust.
And Zealandia, meets all these requirements.
“If you drained the ocean, Zealandia would appear as a plateau standing tall above the ocean floor,” Mortimer said.
Mortimer called it the thinnest, most submerged, and smallest continent.
The problem is, to date, the oldest crust and rock ever taken from Zealandia is only 500 million years old, whereas all the other continents contain crust that is 1 billion years old or more.
However, a new study found that part of the continent of Zealandia is twice as old as geologists thought.
Also read: The Journey of Fried Rice, Born in Southern China to Flying to Various Continents
The continent of Zealandia enters the map
The existence of Zealandia, the eighth continent, became more apparent when geologists mapped its two million square mile area using data from seabed rock samples.
This enhanced map highlights Zealandia’s unique geological history.
Reporting from the Times of India, around 83 million years ago, the Gondwana supercontinent split due to geological forces, giving rise to the continents that exist today.
This process formed Zealandia, where 94 percent of the area is submerged, and only 6 percent of New Zealand and its neighboring islands are visible.
An international team of geologists and seismologists refined existing maps of New Zealand by analyzing rock and sediment samples collected from the seabed and coastal islands.
They complemented this with seismic data analysis and produced a map of Zealandia covering almost 5 million square kilometers.
It took 375 years for scientists to conclude that Zealandia existed, and is now recognized as the eighth continent.
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2023-09-27 15:30:00
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