Scientists say a massive landmass, nearly 1.9 million square miles (approximately 4.9 million square kilometers), has long lain dormant beneath the South Pacific. Known as Zealandia, this mysterious underwater world has remained virtually invisible, with only small portions like New Zealand rising above the water's surface. Now, new geological discoveries have finally revealed the true boundaries of Earth's eighth continent, changing what we know about the planet's ancient past.
How did Zealandia sink beneath the ocean?
Scientists believe the story of Zealandia began over 100 million years ago, when Earth's continents were still united in a single giant supercontinent called Gondwana. This massive landmass encompassed what are now South America, Africa, Antarctica, Australia, and parts of Asia. Over millions of years, Gondwana slowly broke apart, and a drifting fragment eventually became Zealandia.
Researchers led by Nick Mortimer found that powerful tectonic movements gradually pushed Zealandia away from West Antarctica about 85 million years ago, before it separated from Australia. As the landmass became isolated, its crust stretched, thinned, and cooled over time. This weakening caused much of the continent to gradually sink beneath the ocean surface.
New evidence strengthens Zealandia's continental status.
For decades, many geologists suspected that this vast underwater region was more than just a collection of scattered debris. However, without conclusive evidence, the scientific community hesitated to call these submerged plateaus and mountain ranges a true continent, often dismissing them as remnants of larger landmasses.
That perspective has changed thanks to modern technology and new data. Researchers have used geochronology, a specialized technique that measures radioactive decay in minerals to accurately determine the age of rocks, in order to construct an accurate timeline of the region's formation.
Researchers explain that by dating these rocks and studying the magnetic anomalies they exhibit, they were able to map the major geological units across Northern Zealandia.
By collecting samples from the seabed using sophisticated dredging equipment, the research team recovered sandstone, volcanic pebbles, and basaltic lava. These materials, dating from the Early Cretaceous and Eocene periods, provided crucial evidence. The findings confirmed that this hidden mass possessed the same geological DNA found in the seven continents we recognize today, ultimately solidifying its status as a separate world .
Magnetic evidence helps reveal the true shape of Zealandia.
Scientists also relied on magnetic data to uncover the hidden structure of Zealandia beneath the ocean. By studying unusual magnetic patterns buried deep on the seabed, researchers identified traces of ancient volcanic activity that helped outline the boundaries of the submerged continent.
These magnetic signals closely match the age of rocks collected from dredged samples, including vast areas of intraplate basalt formed during the Cretaceous and Eocene periods. This discovery has provided researchers with stronger evidence that Zealandia is not just fragments of oceanic crust.
Instead, organized geological models suggest that the underwater landmass has the same structural pattern seen in recognized continents, further solidifying Zealandia's position as Earth's hidden eighth continent.
Why are scientists fascinated by Zealandia?
Researchers believe that Zealandia offers a rare opportunity to better understand how continents change and evolve as Earth's tectonic plates shift over millions of years. Because most of the landmass remains hidden beneath the ocean, it has preserved geological evidence that may no longer exist on continents exposed above sea level.
A researcher at GNS Science claims that Zealandia's underwater state does not diminish its geological importance.
Scientists say submerged continents provide crucial insight into how plate movements may have reshaped continents over time. Studies of Zealandia's sedimentary rocks suggest that some areas likely remained above water long after landmasses separated from neighboring continents during the Late Cretaceous period. Meanwhile, basalt samples indicate younger periods of volcanic activity that occurred as new tectonic plate boundaries developed.
Even with recent breakthroughs, much of Zealandia remains unexplored beneath the South Pacific seabed. Researchers believe that advanced tools such as seismic imaging and deep-sea drilling could reveal more about the structure, history, and formation of this submerged continent in the coming years.
Future international research and fieldwork are expected to continue exploring Zealandia's role in global tectonic activity and continental movement. At the same time, this discovery continues to spark debate among scientists about what actually constitutes a continent.
Source: GNS Science, Earth.com
Source: https://giadinh.suckhoedoisong.vn/trai-dat-co-luc-dia-thu-8-bi-mat-172260603054800494.htm
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