See New Zealand from the sea
The whole story begins with a sailing expedition by Abel Tasman in 1642. Tasman was an experienced Dutch navigator with a gorgeous figure-eight beard on his upper lip and a thick beard on his chin, and he acted rudely, and on a later voyage, he was drunk and had to hang several of his crew members. On this voyage, he was convinced that there was a vast continent in the southern hemisphere and was determined to find it.
At that time, the southern hemisphere was still quite mysterious to Europeans, but they were convinced that this half of the world must have a vast land mass, and named the yet to be discovered continent "Terra Australis" (Latin, that is, the southern continent) in order to balance and symmetrically the northern continent where Europeans were located. This obsession with a mysterious continent in the southern hemisphere dates back to ancient Roman times, but it was not until the age of discovery that it was validated.
So, on 14 August of that year, Tasman set out from the headquarters of his Dutch East India Company in Jakarta, Indonesia, and led two small sailing ships to the west, then south, and then east, and finally to the South Island of New Zealand. His first contact with the local Māori (indigenous people who began settling here hundreds of years ago) did not go well, and the day after they arrived, several Maori paddled canoes and bumped into a dinghy that was passing messages between two Dutch sailing ships. Four European sailors died. The European crew then returned fire on the 11 Maori canoes, although it is not known whether there were casualties on the Maori side.
Tasman's voyage came to an end, and he named the bay where the death strife occurred "Moordenaers - Murderers Bay", but there was little irony. A few weeks later, he set sail for the return journey without even landing on the newly discovered land. Although he believed that he had indeed discovered the great Southern Continent, it was clear that this was not the business paradise he imagined. He never came back.
(At this time, Europeans knew that Australia existed, but did not consider Australia to be the legendary Southern Continent they were looking for.) But later, the Europeans changed their minds and called the land "Terra Australis", which is the origin of the name Of Australia).)
What Tasman didn't know was that his conviction had always been true: there was indeed a lost continent in the southern hemisphere.
It can be said that Tasman did discover this great southern continent, although he did not know that 94% of the southern continent was under the sea
In 2017, a group of geologists made headlines announcing the discovery of the new continent "Zealandia", known in Maori as "Te Riu-a-Māui", which is the southern continent that Tasman hoped to find. The newly discovered continent covers an area of 4.9 million square kilometers, about six times the size of Madagascar.
Although the world's encyclopedias, maps and search engines are only seven continents, this group of geologists is full of confidence to tell the world that the seven continents are wrong, there are a total of eight continents on the earth, and the newly added Zealand has broken all continental records, and is the smallest, thinnest and youngest continent in the world. What's even more special is that 94% of the area of this new continent, Zealand, is under the sea, with only a handful of islands such as New Zealand protruding from the depths of the ocean.
Zealand has actually been hiding under the noses of humanity.
Andy Tulloch, a geologist at the New Zealand Crown Research Institute GNS Science, said, "Something is obvious and it took a long time to find out that this is an example." "Tallock was part of the scientific team that discovered Zealand.
But this discovery is only the beginning. Four years on, the continent remains as mysterious as ever. Its secrets are hidden deep under two kilometers of water. How did Zealand come about? What kind of life have you ever inhabited? How many long years have you been submerged under the sea? Humans are still confused.
Laboratory findings
In fact, studying Zealand has always been a difficult challenge for the scientific community to overcome.
More than 100 years after Tasman discovered New Zealand in 1642, the British cartographer Captain James Cook was sent on a ship to the southern hemisphere for scientific expeditions. The official instructions given to him were to observe Venus moving between the Earth and the Sun to calculate the Sun's distance from the Earth.
Probably due to geological factors, the closest relative of New Zealand's mysterious Chivi bird is the extinct elephant bird in Madagascar
But Captain Cook also carried a secret letter that he was instructed to unseal after completing his first mission. One of the top-secret missions given by this secret letter is to find and discover the Southern Continent. This task, Captain Cook failed to complete, but in fact before he reached New Zealand, his ship can be said to have crossed the southern continent.
The first real clue to the existence of an unknown continent in the southern hemisphere was found by the Scottish naturalist Sir James Hector. In 1895, he took part in a voyage to explore a series of islands off the southern tip of New Zealand. After studying new Zealand's geological formations, he concluded that New Zealand was "the remnants of a mountain range at the top of a continent extending south and east, which is now submerged underwater..."
Despite this early discovery, knowledge about possible Zealand remained obscure, and until the 1960s there was only a few small advances. Nick Mortimer, a geologist at the New Zealand Institute of Geonuclear Physics, who led the 2017 Zealand expedition, said "research in this area is progressing very slowly".
Then it was the 1960s, when geologists around the world finally reached a consensus on a geological definition of "continent." This broad definition is that, in geological terms, a continent refers to a geological region with a high altitude, a variety of rock species, and a thick enough crust, in addition to which the area must be very large. Mortimer said, "It can't be a small area. "These conditions give geologists the elements to look for new continents. If they can find evidence of these elements, they can prove that the eighth continent is real.
However, the task remains stagnant because finding a continent that meets the above criteria is a difficult and costly task, and Mortimer notes that the task is not urgent. In 1995, the American geophysicist Bruce Luyendyk again pointed out that the region was a continent and suggested that it be named "Zealandia" (or Zealand). Since then, Talok has said that research on Zealand has made an exponential leap forward.
After a bloody clash with the Maori, Tasman's ships left New Zealand, though he believed he had discovered the fabled Southern Continent
Around the same time, the United Nations Convention on the Law of the Sea came into force, ultimately providing a powerful impetus for the discovery of Zealand. The United Nations Convention on the Law of the Sea provides that States may extend their lawful territory beyond the exclusive economic zone (economic sea area), i.e. from the coastline to 200 nautical miles, thus possessing this "extended continental shelf", including all mineral resources and oil contained in the continental shelf.
If New Zealand could prove that its existing territory was part of a vast continent, its territory could increase sixfold. With this inducement, suddenly, the plan to study Zealand was well funded, and the evidence for Zealand's existence was gradually established. Thus, for every rock sample collected, it was a step closer to announcing the discovery of Zealand.
The resulting bulk of the evidence came from satellite data, which could be used to track small changes in Earth's gravitational pull in different parts of the Earth's crust to map the seafloor. With this technology, it is clear to see that Zealand is an irregularly shaped continent, almost the same size as Australia.
British astronaut Pique photographed new Zealand's landforms aboard the International Space Station
The continent of Zealand is finally making its debut to the world, bringing the world's largest territorial waters to one or two countries. Mortimer said, "It's cool, think about it, every continent on earth has a lot of different countries, but Zealand only has three countries' territories." ”
In addition to the entire New Zealand nation, Zealand also includes New Caledonia, a French extraterritorial territory known for its stunningly beautiful lagoons, and Australia's tiny islands, Lord Howe Island and Ball's Pyramid. An 18th-century explorer described the Boer Pyramid Rock as "not yet the size of a ship".
Mysterious Extension
Zealand was originally part of the ancient supercontinent Gondwana, which was formed about 550 million years ago and was essentially the confluence of all the lands of the southern hemisphere. Zealand occupies the eastern corner of the continent of Gondwana, connected to several other land masses, including the western half of Antarctica and the entire eastern part of Australia.
Then, about 105 million years ago, Talok said, "As a result of a process that humans still don't fully understand, Zealand began to break away from this super ancient continent." ”
The continental crust is much thicker than the oceanic crust, usually reaching a depth of about 40 km or so at the center of the earth, while the ocean crust is usually about 10 km thick. As a result of the squeeze, the entire land mass of Zealandia was severely stretched and unfolded, so that the thickness of the Earth's crust became thinner, extending down only 20 kilometres. This continent, which has a very thin crust, although not yet thin enough to reach the level of the general ocean crust, eventually began to sink and disappear under the sea.
Although Zealand's crust is thin and submerged by seawater, according to geological understanding, Zealand is certainly a continent, because a wide variety of rocks have been found in Sealand's crust. Continental crusts are usually composed of igneous, metamorphic and sedimentary rocks such as granite, schist and limestone, while the oceanic crust consists only of igneous rocks such as basalt.
After the Gondwana supercontinent ruptured and disintegrated, the debris drifted apart. The ancient plants that once lived on this ancient continent are still alive in today's Dorigo Forest
Zealand, the eighth largest continent in the world, still has many unsolved mysteries. Its unusual origins have particularly fascinated geologists, and even a little confused. For example, scientists currently don't understand how a continent as thin as Zealand can sustain an entire mass without splitting into tiny land masses.
Another mystery is when Zealand sank underwater and whether Sealand was actually once a large expanse of land above sea level. The part of Zealand that is now above sea level is a ridge formed by the squeezing of the Pacific Plate and the Australian Plate. Talok said that whether Zealand has been submerged underwater except for a few small islands, or whether it was once a completely arid land that was subsequently submerged, scientists are quite divided and inconclusive.
Then the next question is what life once existed on the continent of Zealand.
The ancient continent of Gondwana has a warm climate, covering an area of 11,010 square kilometers, and was once inhabited by a large number of animals and plants, including the earliest tetrapod land animals on Earth, and later a large number of Titanosaurus species, the largest animal in the history of life on Earth. So, are the rocks of Zealand embedded with the remains of these ancient creatures that have been preserved?
The controversy over the existence of dinosaurs
Fossils of land animals are rare in the Southern Hemisphere, but a number of fossils were found in New Zealand in the 1990s, including the ribs of a giant long-tailed long-necked dinosaur (sauropod dinosaur), a beaked herbivorous dinosaur, and an ankylosaur fossil. Then in 2006, the foot bones of a large carnivore were found in the Chatham Islands, about 800 kilometers east of New Zealand's South Island, which may have been a fossil of Allosaurus. The problem is that the animals mentioned above lived after Zealand was divided from the ancient continent of Gondwana.
The elephant bird that once lived in Madagascar is 3 meters tall, and although it is extinct, fragments of elephant egg shells are still scattered on the beaches of Madagascar today
However, the presence of these fossils does not necessarily mean that dinosaurs once lived in most parts of the continent of Zealand, and most of the land of Zealand, as it is today, when it sank underwater, the islands where the fossils were found may have been the only habitat for dinosaurs. Rupert Sutherland, a professor of geophysics and geotectonics at Victoria University of Wellington, said, "There is no patch of land, whether there is a possibility of land animals, and whether land animals will go extinct without patches of land, this question has been debated for a long time." ”
The puzzling story of Zealand is further complicated by New Zealand's wacky and beloved animal, the kiwi. The Chivi bird is a short, round, feathered bird with whiskers. Curiously, the species closest to the Chiwei bird is not a moa bird (Moya bird) that also does not fly and lives in New Zealand until 500 years, but a larger elephant bird that is far away in the forests of Madagascar and became extinct 800 years ago.
The discovery led scientists to believe that the common ancestor of the Chivi and elephant birds was a certain bird that lived on the ancient continent of Gondwana and later evolved in different places. The complete dissolution of the ancient continent of Gondwana took 130 million years, and fragments of the divided continent were scattered around the world, forming today's South America, Africa, madagascar, Antarctica, Australia, the Arabian Peninsula, the Indian subcontinent and Zealand.
This means that at least part of Zealand, which is now submerged, was at least at sea level. Scientists believe that it wasn't until about 25 million years ago that the continent of Zealand, and possibly even all of New Zealand, was submerged in the water. Susseland said, "People think that all the plants and animals on New Zealand land migrated after this. "What happened to Zealand at that time?"
New Zealand is the highest point in Zealand, a ridge formed by the impact of plate movement
While it is not possible to collect fossils directly from the seafloor of Zealand, scientists have been drilling deep into The Sealand crust to sample. Suseland said, "Actually, the most helpful and easily identifiable fossils were formed in very shallow shallow seas. Because these shallow seas have left a record, there are countless very, very small, and very recognizable fossils. ”
In 2017, a team conducted the most extensive survey of the area, sampling more than 1,250 meters deep from the ocean floor down at six different sites, and its collection of cores contained pollen from terrestrial plants, as well as spores and shells of organisms that live in warm shallow seas.
Suselan said, "If you see a piece of water, only one piece of water, the depth of the water is only about 10 meters or so, then there is a good chance that there is land not far away." He explained that the presence of pollen and spores in shallow seas also suggests that Zealand may not have been submerged in water all the time.
Distortion of the terrain
The shape of Zealand is also a puzzle.
Susseland said, "If you look at the geological map of New Zealand, you will find two striking phenomena. "One is the Alpine Fault, which runs through the South Island, the boundary between the two plates, so conspicuous that it can be seen from space.
Satellite maps show the east coast of New Zealand's South Island
Second, New Zealand, and the larger continent of Zealand, exhibit strange distortions in their geological formations. New Zealand and the continent of Zealand, where it is located, are divided into two parts by a horizontal line that is the junction of the Pacific Plate and the Australian Plate. But curiously, right at this demarcation, it appears that the lower half of the continent of Zealand is distorted by some force, so that the previously continuously extended belt of rock is no longer linear and almost twisted at right angles.
The simple explanation for this phenomenon is that the movement of the earth's crust plates leads to the deformation of the original geological structure. But if you ask further how and when this happened, there is still no satisfactory answer.
Talok said, "There are many opinions, various interpretations, and it is still a considerable unsolved problem." ”
Susseland explained that the continent of Zealand could not reveal all its secrets anytime soon. "All the secrets are 2 kilometers underwater, so it's hard to spot, and the formation you need to sample is also 500 meters deep under the seabed," he said. Exploring such an underwater continent is really challenging. Therefore, we need to spend a lot of time, money and energy to go out to sea by boat and explore underwater. “
If nothing else, the eighth continent certainly shows that nearly 400 years after Tasman embarked on his voyage of discovery of the Southern Continent, the New World of Zealand is still shrouded in fog and there are many secrets to be explored.
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