Scientists led by geologist Dr. Johann Klages are studying the results of X-ray scans. They’re using a machine at a hospital in Germany to investigate cores they’ve drilled in the Amundsen Sea off the Antarctic coast. And the results that the CT (Computed Tomography) scan gives them are totally astonishing. They’ll radically change the way we view the Cretaceous period of 90 million years ago, the peak time of the dinosaurs.
Klages and his team had obtained their core samples in 2017 in icy waters just off Pine Island and the Thwaites glacier in the Western Antarctic. They were drilling from the research vessel Polarstern some 560 miles from the South Pole. Using a specialist rig, MARUM-MeBo70, they were probing down some 80 feet beneath the seabed.
Germany’s Alfred Wegener Institute, based in the city of Bremerhaven, was the lead organization for this international expedition to the Antarctic. The establishment runs research programs in the Arctic and Antarctic regions as well as the North Sea. Other bodies involved included Imperial College London’s Earth Science and Engineering Department and the Northumbria University in Newcastle upon Tyne, U.K.
The scientists’ mission on their 2017 expedition was to drill for and collect sediments from below the seabed of Antarctica’s Amundsen Sea. These deposits would help researchers to understand the geological past of the continent. This in turn would allow them to construct the ancient Antarctic climate and to gain a better understanding of how modern warming might impact the continental ice sheet.
The research team travelled to the Amundsen Sea aboard the icebreaker Polarstern, embarking from the city of Punta Arenas in the far south of Chile in February 2017. Their route took them through the Strait of Magellan and on into the Pacific. Immediately they hit the ocean, a storm blew up around them.
Fortunately this would be the only storm the Polarstern would face in the next few days. Then they began to see icebergs as they approached their destination in the Amundsen Sea. We’ll get back to the research team aboard the icebreaker shortly, but first let’s learn more about the southernmost continent, Antarctica.
The Antarctic is the continent and various adjacent islands that surround the pole, with the mainland mass covering some 5.4 million square miles. By way of comparison, the U.S.A. contiguous mainland states cover some 3.2 million square miles. Something like 98 percent of Antarctica is covered by ice which first began to form roughly 45 million years ago.
As you’d expect in a land perpetually covered in ice, the Antarctic is cold. Extremely cold. Average temperatures through the year range from a summer high of 14°F to a winter low of -76°F. The lowest satellite-measured temperature, recorded in 2010, was -136 °F. What’s more, gale-force winds and blizzards resulting in complete white-out conditions can last for days at a time.
The vast majority of Antarctica’s mainland is covered in a massive ice sheet which is an average of one mile deep and includes some 90 percent of all ice on the planet. Around 70 percent of the Earth’s fresh water is locked into that ice. Although it’s an unlikely eventuality in the coming centuries, if all that ice were to melt sea levels around the world would rise by more than 200 feet.
There are no permanent human residents on Antarctica’s mainland, although a few thousand scientists and support staff visit each year. There is also a thriving cruise ship and fly-over tourist industry, with some 40,000 visitors during the summer season from November to March. When Antarctica was discovered it had no indigenous human population, the only continent where that was so.
Travel back through time to some 170 million years ago and our planet had a supercontinent called Gondwana which included the land that would eventually break off and drift south to become Antarctica. The continent we know today dates back to roughly 25 million years ago, although as we’ve seen the land mass started to ice over about 45 million years ago.
The freezing of Antarctica accelerated about 34 million years ago after carbon dioxide levels had decreased from highs in the several thousand parts per million (ppm) to circa 760 ppm. The CO2 levels continued to drop and scientists believe that a level of 600 ppm was low enough to trigger a large increase in ice coverage.
Since that glaciation all those tens of millions of years ago, the ice sheet has remained remarkably stable. There was some melting between three and five million years ago during the warmer period of the Pliocene. However this applied only to the Western Antarctic, while the ice sheet of the Eastern Antarctic remained largely unaffected.
It was late in the day before humans finally reached the Antarctic and even then it was by accident rather than design. An Englishman, Anthony de la Roché, was the first person we know of to visit Antarctica. In 1674, the merchant embarked on a trading voyage from Europe to South America when storms drove his ship far to the east of Cape Horn.
On his second great voyage of exploration, Captain James Cook crossed into the Antarctic Circle aboard the HMS Resolution in January 1773. Cook and his crew were the first to reach this region. The captain formed his theory that on the other side of the impenetrable ice floes he’d encountered there would be land.
It would be 1820 before Cook’s theory was proved right. In that year, two Russian explorers, Mikhail Lazarev and Fabian Gottlieb von Bellingshausen, were the first men to reach mainland continental Antarctica. Neither of the expedition’s two ships landed on the Antarctic Peninsula in 1820, but they saw its coastal ice fields.
Although it’s still controversial, many believe that the first man to actually set foot on the Antarctic continent was an American sealer called Captain John Davis. He claimed that he had landed there in 1821. For years after that, most of those who made it to the Antarctic seas were commercial sealers or whalers rather than explorers or scientists.
Sir James Ross, an officer with the British Royal Navy, led an expedition in 1839 in an attempt to reach the South Pole. After four years, the mission was unsuccessful although various parts of the Antarctic, mainly along the southern coast, were explored for the first time. Other explorers were also unable to make significant sorties into the interior of the ice-clad continent.
This was to change towards the end of the 19th century and on into the early 20th century when a series of expeditions were launched. This was the era that produced such notable figures as the British explorer Ernest Shackleton. His Nimrod Expedition from 1907 to 1909 succeeded in reaching a spot 112 miles from the South Pole.
In 1910 two expeditions set off in a bid to reach the South Pole. One was led by Briton Robert Falcon Scott and the other by the Norwegian Roald Amundsen. Amundsen reached the pole first in December 1911, while Scott followed him 33 days later. On their return journey Scott and his team of four all lost their lives, killed by hunger and freezing temperatures in the extreme Antarctic conditions.
From 1929 Antarctic exploration was increasingly mechanized, both by land and by air. Captain Finn Ronne of the U.S. Navy led one such expedition from 1947 to 1948. His team was equipped with three planes as well as dogs. Ronne’s survey proved that Antarctica was one single entity. Previously, many had believed it was divided into two parts, East and West Antarctic.
Intensive exploration continued in the following decades but today scientists continue extensive research on the massive frozen continent to unlock its secrets. As many as 4,000 scientists visit Antarctica’s frozen wastes every year. However, as hostile as the environment is, there are some flora and fauna that make Antarctica their home, or at least visit regularly.
Several species of bird fly across Antarctica including petrels, albatrosses and South Georgia pipits. With some 20 million breeding pairs, penguins are the most common birds on the continent. Six different seal species are found in the Antarctic including leopard, crabeater and Weddell seals. Once extensively hunted for their skins, all seals species in Antarctica are now protected. Killer whales are the main danger for the seals today.
Fish species found in Antarctic waters include icefish and toothfish, and colossal squid also swim in the seas. Unsurprisingly in a land almost completely covered in massively thick ice year-round, plant species are few and far between. In fact there are only two flowering plants found on the continent, hair grass and pearlwort. These are complemented by various types of lichen, moss, fungi and liverworts.
It’s time we got back to Dr. Johann Klages and his team, whom we left as they traveled aboard the icebreaker Polarstern in February 2017. They were heading towards the Amundsen Sea for their research mission. The ship sailed through ice fields which were unusually sparse for the time of year and on into the Antarctic Circle, stopping at Thurston Island.
The expedition took the opportunity to test out the MeBo drilling rig for the first time in Antarctic conditions. The rig was submerged to a depth of 3,300 feet below the sea surface. Once on the seabed, it drilled down 75 feet, although it can penetrate to just over 260 feet. This first sample was something of a disappointment as it contained few microfossils.
Those microfossils are important to the scientists because they can be used to date drilled sediment cores.But the expedition was not yet at its main target area, where the team would hope to get more rewarding results. Now RV Polarstern headed for the Pine Island Glacier basin, the principal site the research team planned to investigate.
As the team drilled into the seabed there were varying results but then a core came up with dark mudstone from beneath the granite seabed. That meant they had hit sediment laid down many millions of years ago when the Antarctic climate was much warmer – exactly what they were hoping to find. However, the researchers would have to wait for lab analysis to know just how interesting this core and others like it were.
By now the expedition was into its fifth and final week. After more drilling and recovery of cores it would be time to head back to Punta Arenas. Soon experts would be minutely scrutinizing the many samples that the Polarstern had collected to extract information from them. But the scientists knew they already had a first – retrieving core samples from sedimentary rock laid down before Antarctica was covered in ice 45 million years ago.
As it turned out, it was the very last sample that the geologists drilled from below the seabed which provided the most groundbreaking information. But as the researchers worked, a massive ice sheet was moving menacingly towards the Polarstern. Klages told The Guardian newspaper in April 2020, “It was getting a little dangerous.”
The threat was that the ice sheet might cut into the cables that connected the MeBo drilling rig to the Polarstern. This would be a disaster since it would be practically impossible to retrieve this extremely expensive piece of high-tech kit if it was lost on the seabed. But as Klages recalled, “We said: ‘Okay, three more meters and then we can evacuate the coring site here.’ And in these three meters we had this exciting new material.”
And this core, encased in a canister, had the dark, muddy material that suggested it was from the time before Antarctica’s glaciation. Speaking to Discover Magazine in April 2020, Klages recalled, “No one had ever seen anything like that, so we decided not to open [the canister] onboard. It would have been too risky to the material.”
Even although they didn’t examine the contents of the core in detail, Klages was already excited by what they’d found.Speaking to TV news channel CNN he said, “During the initial shipboard assessments, the unusual coloration of the sediment layer quickly caught our attention; it clearly differed from the layers above it. We had found a layer originally formed on land, not in the ocean.”
Once the team had the sample in the lab, it proved to be every bit as exciting as they’d hoped. A CT scan revealed that the earthy material contained a mass of roots and plant material. Klages told the Vice website, “We saw these amazing, pristine, complete, dense networks of fossil roots in the core connected down to the core base.”
Klages continued, “If you go to the forest in front of your house, or somewhere, and you drill a hole, you would get something very similar. It was full of pollen and spores and really diverse assemblages.” Now the scientists were to spend three years engaged in a painstaking analysis of the material they’d retrieved.
One of the first tasks was to fix upon a date for the age of the material in the core. Analysis of the clay and silt in the sample showed that it had been laid down some 90 million years ago. That was the epoch of the mid-Cretaceous, a time when dinosaurs strode the Earth.
As Klages pointed out to Discover Magazine, “It is definitely the southernmost Cretaceous evidence ever recovered on the planet. We were the first ones to ever drill there in that environment.” But did dinosaurs once roam Antarctica before it became an icy desert? Klages admits that this is a difficult question.
By way of an answer Klages said, “It’s very likely that there were insects and dinosaurs and all of that there too, but we can’t say for sure because we did not find anything like that. We only can say a lot of stuff about the paleobotany that we found in the core.” However what we can be sure of is that 90 million years ago Antarctica was a land of warm, temperate forests.
And these forests somehow survived at a latitude of 82 degrees south, which means that every year they would have lived through four months of complete Antarctic darkness. The scientists speculate that the forests may have survived these long periods without sunshine by exploiting high levels of carbon dioxide in the atmosphere. In fact these ancient forests have prompted scientists to revise their estimates of CO2 levels for the period upwards.
It’s hard to imagine, but there is no doubt now that Antarctica hosted thriving forests 90 million years ago. And summer temperatures would have averaged about 66°F. As Klages said, “It really was that warm. That amazed us, of course, but also the climate modelers because no one expected such extreme values very close to the South Pole.”