Scientists who embarked on an expedition to explore Zealandia, Earth's "lost continent" that lies underwater, have returned with information that unveils some of the region's secrets.
Lost 8th Continent
Zealandia, which encompasses New Zealand and lies just east of Australia, is a sunken mass of land about as big as India. Earlier this year, scientists argued that this narrow strip of land, whose landmass mostly lies 3,280 feet below the sea, could be the long-lost brother of the seven known continents.
In February this year, GNS Science geologist Nick Mortimer and colleagues contended why Zealandia qualifies as a continent.
"Its isolation from Australia and large area support its definition as a continent — Zealandia. Zealandia was formerly part of Gondwana. Today it is 94% submerged, mainly as a result of widespread Late Cretaceous crustal thinning preceding supercontinent breakup and consequent isostatic balance," the researchers wrote in GSA Today.
Expedition To Study Zealandia
For two months, 32 scientists from the International Ocean Discovery Program (IODP) explored the region. The researchers drilled into the seabed to retrieve sediment cores, which contain records of life dating back millions of years and offer clues as to how volcanism, geography and the climate of Zealandia have evolved over time.
"Zealandia, a sunken continent long lost beneath the oceans, is giving up its 60 million-year-old secrets through scientific ocean drilling," said U.S. National Science Foundation's Division of Ocean Sciences program director Jamie Allan.
Zealandia is thought to have submerged when it broke off from Antarctica and Australia about 80 million years ago but it is now clear that later events helped shaped the continent that exists today.
New fossil discoveries revealed that Zealandia has not always been as deep under the waters as it is today. The microscopic shells of organisms that live in warm and shallow seas, and the spores and pollen of land plants, likewise revealed that the climate and geography of Zealandia were dramatically different in the past.
Scientists also found evidence suggesting that the formation of the Pacific Ring of Fire between 40 and 50 million years ago caused dramatic changes in volcanic activity and ocean depth, as well as buckled Zealandia's seabed.
Scientists said that the big geographic changes may help shed light on how animals and plants spread and evolved in the South Pacific. The discovery of shallow seas and past land revealed pathways that plants and animals used to move along.