On a research ship in the South Pacific, scientists are drilling thousands of feet beneath the waves, and with each sample, they learn more and more about Earth’s hidden eighth continent. It’s a landmass that has remained a mystery for millions of years – but what secrets will Zealandia finally reveal?
As any good student knows, our planet is made up of seven continents: Africa, Asia, Australasia, Europe, North America, South America and Antarctica. However, back in 1995, American scientist Bruce P. Luyendyk suggested that an eighth, hidden continent lies beneath the waters of the Pacific Ocean.
Then, over time, the theory of Zealandia began to take shape. According to researchers, the landmass broke off from Australia some 80 million years ago. Today, moreover, it’s thought that some 93 percent of the region is under the ocean. Some parts, such as New Zealand and New Caledonia, remain above water, however.
At almost two million square miles, Zealandia is approximately the same size as the Indian subcontinent. Fascinatingly, too, it’s home to various Antarctic flora, suggesting that both landmasses were once joined as part of the supercontinent known as Gondwana.
Now although it is officially recognized as a microcontinent, many now believe that Zealandia should be considered a continent in its own right. In fact, in February 2017, a team of researchers from New Zealand, Australia and New Caledonia released a paper that laid out their support for such a claim.
According to the paper, Zealandia satisfies all of the necessary geographical criteria required for it to be classified as a continent. Apparently, these include the thickness of its crust, its specific geology and how high its continental shelf is. However, not everyone agrees.
Christopher Scotese, who specializes in ancient geography at Northwestern University, doesn’t quite believe that Zealandia is its own continent. “If it were emergent, we would readily identify it with Australia,” he told National Geographic in February 2017. “Much like we identify Greenland with North America and Madagascar with Africa.”
Yet while scientists continue to debate Zealandia’s official status, there can be no doubt that we still have much to learn about this fascinating lost land. So much, in fact, that an international team of investigators from the Integrated Ocean Drilling Program (IODP) decided to launch a groundbreaking survey of the controversial continent.
Then, on September 27, 2017, the researchers announced the results of their expedition. For two months, the team had traveled the Pacific Ocean on board JOIDES Resolution, a drilling ship operated by the IODP. And over the course of the study, they visited six separate sites across Zealandia.
While at each site, researchers drilled down into the seabed to collect samples from the continent’s crust. At points, they had to descend through almost 16,000 feet of ocean to reach the bottom. Then, once there, they continued to drill to a depth of some 8,200 feet.
From the drill sites, researchers were able to recover sediment cores that revealed some fascinating insights into the history of Zealandia. In fact, a staggering 8,000 fossil specimens from hundreds of different species were recorded over the course of the expedition.
Interestingly, these findings seem to suggest that Zealandia was once a very different place. “The discovery of microscopic shells of organisms that lived in warm shallow seas, and spores and pollen from land plants, reveal that the geography and climate of Zealandia was dramatically different in the past,” expedition co-chief Gerald Dickens, from Texas’ Rice University, was widely quoted as explaining.
In fact, the team’s research suggests that Zealandia has undergone many changes over the years – both in terms of what it has looked like and which organisms have thrived on its land. Perhaps most significant, however, are the tectonic shifts believed to have taken place in the continent’s past.
“The new discoveries reveal that the formation of the ‘Pacific Ring of Fire’ about 40 to 50 million years ago caused dramatic changes in ocean depth, volcanic activity, and buckled up the seabed of Zealandia,” Dickens continued. Interestingly, too, he went on to explain that although the continent could well have been submerged when it first broke off from Australia, later events may have had an equally significant impact on the landmass.
Apparently, scientists now suspect that the surface of Zealandia might have been far closer to land level than was previously believed. And, if this is the case, it could transform our understanding of how different life evolved throughout the region.
“[The research] has big implications for understanding big scientific questions,” Professor Rupert Sutherland, from Victoria University in New Zealand, explained. “Such as how did plants and animals disperse and live throughout the South Pacific?”
And in Zealandia, Sutherland believes that they may have finally found the answer to this question. “The discovery of past land and shallow seas now provides an explanation,” he continued. “There were pathways for plants and animals to move along.”
For the scientists on board JOIDES Resolution, the findings have been a revelation, too. “The cores acted as time machines for us, allowing us to reach further and further into the past,” enthused researcher Stephen Pekar on the expedition blog. “As one scientist put it: ‘We are rewriting the geologic and tectonic history of Zealandia at the drill site.’”
Yet although researchers are excited about the findings of the expedition, the project is far from over. In fact, the JOIDES Resolution is set to embark on further travels, collecting more data from sites around New Zealand, Antarctica and Australia.
Meanwhile, it seems that the team’s research may have even further-reaching applications. As the need for accurate computer models to predict climate change becomes ever greater, records like those from the lost continent could be used to calibrate and refine emerging technology. So, Zealandia might continue to shape the Earth for many years to come.
Now, as you may be aware, Antarctica is the continent that is particularly threatened by climate change. But that’s not all that this giant icy mass has to contend with. Yes, new research has made experts more aware of the volcanic activity that is happening beneath the ice sheet. And it could be very bad news for both the continent and the entire planet.
Because of its remoteness, intense cold and extreme weather events, Antarctica is one of the least explored parts of our planet. As a consequence, it’s also one of the least understood parts of the Earth. Consequently, scientists continue to learn about the geology and geography of this supremely hostile environment. And some recent research clarifies the extraordinary forces at work beneath the Antarctic ice cap.
About twice the size of Australia, Antarctica is the world’s fifth-largest continent, and it is, of course, the location of the South Pole. The continent sits in the Southern Ocean and has a surface area of about 5.4 million square miles.
Temperatures on this most frigid of continents can sink to as low as a bone-chilling ?129 °F. However, average temperatures during the Antarctic winter average a slightly balmier ?30 °F. The warmest summer temperature ever recorded was 59 °F, not quite sunbathing weather.
In fact, the continent has only two seasons – summer and winter. The summer consists of six months of daylight, while the winter is the exact opposite – six months of no light. About 98 percent of Antarctica is covered in ice. On average, this ice is a staggering 1.2 miles thick.
That amount of ice is by volume about 90 percent of all the fresh water on our planet. If it all melted, that would raise the level of the world’s oceans by some 230 feet. In the eastern part of Antarctica, the ice sheet sits atop a land mass, but in the west the ice extends into the ocean by as much as 8,200 feet.
Antarctica is so remote that although there was speculation about the existence of a southern land mass, it was 1820 before the continent was actually discovered. A Russian expedition led by Fabian Gottlieb von Bellingshausen and Mikhail Lazarev was the first to sight Antarctica. But it wasn’t until 1895 that a party of Norwegians actually landed on the icy continent.
It was in 1907 that the British explorer Ernest Shackleton led a team that penetrated the interior of Antarctica, becoming the first explorers to reach the magnetic South Pole. In December 1911, the Norwegian Roald Amundsen and his men were the first to reach the geographical South Pole.
Amundsen’s great rival, the British explorer Sir Robert Scott, reached the South Pole in January 19o8, pipped to the post by the Norwegian by just a month. Arguably though, Scott’s expedition came to be the more famous because of the ultimate fate of its members.
Returning to base camp after their trip to the South Pole, Scott and his team missed a rendezvous where they would have been resupplied. Captain Oates made his famous departure from the expedition tent to certain death, hoping that this might leave enough supplies for the others. But the three remaining men, including Scott, all died.
Today, some tens of thousands of tourists visit Antarctica during the summer months, and a few thousand scientists spend tours of duty on the continent each year. But Antarctica is still a place that can be fraught with danger, even for well-equipped scientific expeditions and bases.
One of the most sophisticated of the Antarctic scientific bases, the British Halley VI, well illustrates the dangers of this isolated continent. Halley VI is designed to be moved, comprising independent, linked units mounted on sleds. In 2015 the station was indeed moved some 14 miles because of the perceived threat presented by a large crack that had appeared on the ice sheet where it was located.
But despite this move, the station had to remain unstaffed for the winter months for two seasons after that. So scientific exploration of the Antarctic remains a highly risky and difficult pursuit. But one team of scientists from NASA has come up with fascinating new information by using a clever combination of existing knowledge and data from other parts of the world, including Hawaii and Yellowstone National Park.
The NASA scientists have been studying an area called Marie Byrd Land, which is in west Antarctica. Their interest was in exploring the possibility that underneath this territory lies a massively hot geothermal phenomenon known as a mantle plume, causing volcanic activity. Such a plume exists beneath Yellowstone National Park and is the source of the intense geothermal activity there.
In fact, it was theorized as long as 30 years ago that there might be a mantle plume beneath Marie Byrd Land causing volcanic activity. But scientist Hélène Seroussi said on the NASA website that when she first heard about the theory, “I thought it was crazy. I didn’t see how we could have that amount of heat and still have ice on top of it.”
Seroussi and her NASA Jet Propulsion Laboratory colleague Eric Ivins knew that there were few actual measurements of what was happening under the ice. So they opted to use a modeling technique for their study. They refined and developed an existing tool called the Ice Sheet System Model for the purposes of their study.
As a reality check, the scientists compared their results with actual measurements of ice melt made by a NASA satellite and an airborne operation. Their findings indicated that the heat generated by the mantle plume must be about 150 milliwatts per square meter. For comparison, the Earth’s crust generates about 40 to 60 milliwatts in places with no volcanic activity. Yellowstone Park averages 200 milliwatts.
The diagram here shows the complex pattern of rivers and lakes that run beneath the ice at Marie Byrd Land. Lakes are denoted by blue dots, while the lines represent rivers. The scientists now believe that much of this activity under the ice is caused by the heat emanating from the mantle plume.
This plume is a result of a rupture in the Earth’s crust that allows molten magma to flow beneath the ice. This type of rift is similar to that which lies below the Great Rift Valley in Africa and is also present under Yellowstone and Hawaii.
The rift beneath Marie Byrd Land appeared some time between 50 million and 110 million years ago. This was time when the Antarctica land mass was not covered in ice. Now the ice sheet that is there is greatly affected by the thermal activity beneath. Crucially, the very stability of the ice sheet depends on the amount of liquid water at its base.
We know that the Antarctic lost much of its ice sheet 11,000 years ago as the last ice age ended. Increasing temperatures then caused substantial sea level rises. The question now is, what will global warming combined with thermal activity do to the ice sheet? Don’t forget that figure of a 230-foot sea level rise if all of the Antarctic’s ice were to melt. Only time will tell how much we need to worry.