General knowledge says that there are seven continents on Earth namely Asia, Europe, Africa, North America, South America, Australia and Antarctica.
However, scientists have made a startling discovery of a hidden continent named "Zealandia." The 11 geologists involved in the study stated that the southwest region of the Pacific Ocean located to the east of Australia, which contains New Zealand and New Caledonia, is actually a continent of its own.
The study is featured in GSA Today and states that Zealandia, which was once part of the long-lost ancient supercontinent called Gondwana, is a 4.9-million-square-kilometer slab of continental crust situated southwest of the Pacific Ocean.
The study was conducted by 11 researchers namely, Nick Mortimer, Hamish J. Campbell, Andy J. Tulloch, Peter R. King, Vaughan M. Stagpoole, Ray A. Wood, Mark S. Rattenbury, Rupert Sutherland, Chris J. Adams, Julien Collot and Maria Seton.
Discovery Of Zealandia
The term Zealandia was first coined in 1995 by Bruce Luyendyk, a geophysicist at the University of California, Santa Barbara.
However, according to Luyendyk, the name was given to describe New Zealand, New Caledonia, and a collection of submerged pieces and slices of crust which were part of the Gondwana supercontinent.
The researchers went a bit further and decided to re-examine Luyendyk's idea by decoding the existing evidence under four basic criteria. The geologists referred to a number of criteria to deem a slab of rock as a continent.
The four basic criteria are:
One: If the land jolts up comparatively higher from the ocean floor.
Two: The crust must contain all the three types of rocks namely metamorphic, sedimentary and igneous.
Three: The slab of crust must be thicker and less dense compared with the thickness of the surrounding ocean floor.
Four: There must be well-defined boundaries surrounding an area large enough to be considered as an continent, rather than terming it a micro-continent or a fragment of any continent.
Both New Zealand and New Caledonia fulfill the first three criteria, enabling the researchers to coin the term Zealandia for the new continent.
At first glance, the continent seems to be broken, but based on the results of the study — which used satellite-based elevations and gravity maps — Zealandia indeed looks part of the unified region.
Zealandia And Its Characteristics
The study states that Zealandia is a part of former supercontinent Gondwana. Zealandia is also the youngest and the thinnest of all other continents on Earth.
Nearly 94 percent of Zealandia is currently submerged, which Mortimer says is nothing unique.
"It is not unique in this regard: an ice-free, isostatically corrected West Antarctica would also largely be submerged," said Mortimer.
The new continent once made up approximately 5 percent of supercontinent Gondwana.