1912 (41 page)

The answer to why coal was in Antarctica lay within the sixteen kilograms of samples Scott and his team had collected and dragged to their deaths. With the publication of
Scott's Last Expedition
, a collection of the British leader's journals, the public learned that on discovering the dead men the search party ‘recovered all their gear and dug out the sledge with their belongings on it. Amongst these were 35 lb. of very important geological specimens which had been collected on the moraines of the Beardmore Glacier; at Doctor Wilson's request they had stuck to these up to the very end, even when disaster stared them in the face and they knew that the specimens were so much weight added to what they had to pull.'

The remaining expedition members immediately saw their scientific value. The geologist Griffith Taylor remarked that the ‘specimens brought back by the Polar Party from Mt. Buckley contain impressions of fossil plants of late Palaeozoic age, some of which a cursory inspection identifies as occurring in other parts of the world. When fully examined, they will assuredly prove to be of the highest geological importance', while his colleague Frank Debenham argued that their preservation would allow people to ‘settle a long-standing controversy between geologists as to the nature of the former union between
Antarctica and Australasia'. But what precisely the specimens were was not widely known.

Buckley Island—or Mount Buckley, as it is sometimes referred to—is a nunatak atop the Beardmore Glacier. It was here, on the return from the pole, that Edward Wilson found the coal deposits reported by Shackleton. The men spent the afternoon of 8 February 1912 and some of the following morning under the cliff face. Searching among the jumble of rocks they scanned the surface for samples, splitting promising-looking blocks of stone in the search for elusive fossils while the eagle-eyed Wilson made detailed notes. On close inspection some were found to contain the clear impression of ancient leaves.

Today these delicate samples are carefully preserved in London's Natural History Museum, locked away in small cardboard boxes, hidden among a global collection that has been gathered over centuries. It is hard to believe these small rocks, several centimetres across and rough-edged, are the same ones that caught Wilson's eye all those years ago. The scientist described them as ‘dark blackish slaty, shaly or coaly matter, some exceedingly hard, some splitting easily, and some breaking vertically into blocks', where ‘the best leaf-impressions and the most obvious were in the rotten lumps of weathered coal which split up easily to sheaf-knife and hammer. Every layer of these gave abundant vegetable remains. Most of the bigger leaves were like beech leaves in shape and venation, in size a little smaller than British beech, and the venation were much more abundant and finer in character, but distinctly beech-like.' The romance of their effort was not lost on Markham, who commented: ‘There is no more glorious and more touching event in the whole range of polar history.'

At the time of David's 1914 talk in London, work on these fossils was nearing completion at the University of Cambridge.
Working on the precious samples, Albert Seward, a professor of botany, reported in the first of several natural-history accounts from the expedition that some of the fossils were
Glossopteris
, the ubiquitous Gondwanaland flora that David had referred to in his Dunedin talk a decade before. Seward wrote: ‘the discovery of
Glossopteris
on the Buckley Island moraine supplies what is needed to bring hypothesis within the range of established fact.'

Here was proof that Antarctica had not only been warmer in the past: it had somehow been linked to South America, India and Australia at the centre of Gondwanaland. If the botanist Marie Stopes had been influential in encouraging Scott and his team to collect them after their heady night of dancing years before, it was serendipity indeed.

The simplest explanation for how
Glossopteris
came to be in Antarctica was through one of the hypothesised land bridges connecting the southern continents. In the oceans, however, the much-sought evidence had remained elusive. As part of the Australasian effort the expedition ship
Aurora
had made several vast sweeps of the Southern Ocean, taking soundings for water depth and trawling the sea for biological evidence of an ancient link. Even though Mawson was keen to find proof, he was not convinced by what they had found. The most promising was the Mill Rise, which Davis had discovered south of Tasmania, but this was an isolated plateau and did not span nearly enough of the ocean to make the case.

David did not give up on the idea of a land bridge, and contacted Teddy Evans and the crew of the
Terra Nova
about making depth soundings in a different sector of the ocean to the Australasian party. Shortly before the British set off to collect Scott and his men, David wrote to Evans: ‘King Edward Land and the land found by Amundsen and Lieutenant Shirase southwards from King Edward Land shows that the land probably
consists of some very large and low islands, forming an almost continuous land mass, at the foot of the Antarctic Andes further south, in fact an island group analogous to that of the Palmer Archipelago and of the South Shetlands. There should be sunken islands to the north of King Edward VII Land and you might be lucky enough to locate some of these or the submarine Plateau on which they rest.'

He was convinced that ‘there is no part of the ocean more intensely interesting scientifically than that which lies between the South end of New Zealand and the Ross Sea.' The measurements were made, but there was no sign of a land bridge there either. So how did
Glossopteris
come to be in Antarctica?

Bold new scientific ideas were coming to the fore as the Antarctic expeditions returned home. Alongside reports proving the existence of the atom and the discovery of a possible fossilised human species in England, a little-known German scientist called Alfred Wegener was suggesting something more controversial: the world's continents formed part of an enormous jigsaw.

By 1912 Wegener was publishing scientific papers on his solution to the confusing observation that distinctive fossils were found across many continents. Later developed in a landmark book called
The Origin of Continents and Oceans
, his ideas were not published in English until 1924, delaying their discussion among the wider scientific community. Wegener proposed that you did not need drowned land bridges to account for similar geological formations in disparate locations. Instead, everything could be resolved if the continents had ploughed their way through the oceans—which Wegener described as displacement theory—changing their location on the surface.

Gondwanaland had been one massive supercontinent and,
instead of parts sinking into the world's oceans, it had split and the continents drifted apart from one another during the Jurassic period, which began around 161 million years ago. If the thinking was correct, it meant the Antarctic coal was no longer in the location where it had formed: Gondwanaland had torn apart and created the world we see today.

Not everyone in the scientific community welcomed this theory. Critics were scathing, largely because there was no evidence for how Wegener envisaged the continents moved across the surface. Comments such as ‘German pseudo-science' and ‘purely fantastic' indicate the depth of feeling. It was not until the 1960s that Wegener's ideas became widely accepted, once it was recognised that it wasn't the continents that moved per se but the plates on which they sit and float. Plate tectonics was able to explain how new continents and oceans were created, destroyed or rubbed along uncomfortably together.

Ironically, a focus of the Australasian effort, Macquarie Island, is now known to lie on the eastern boundary of the Indo-Australian Pacific Plate, explaining the frequent earthquakes experienced by Mawson's men. It was not enough, however, to convince the Australian leader, who remained distinctly cold to the idea, though David did come round to the concept. More importantly, though, continental drift suddenly made it possible to argue that the Antarctic coal measures had formed in lower latitudes and then moved on. But was this the whole story?

During a long spell in our planet's history, 299 to 251 million years ago,
Glossopteris
dominated the Gondwanan scenery. But it was not the only thing growing in the landscape. The diversity of Antarctic vegetation found alongside
Glossopteris
was relatively low, implying cooler conditions. More significantly, associated deposits were found to contain magnetic particles that sit close to vertical—the same principle behind dipping compasses—proving Antarctica was close to the magnetic pole
at the time of
Glossopteris
and the formation of coal. It appeared that Antarctica had not been that far north, after all: at least, not far enough to avoid several months of twenty-four-hour darkness each year. And yet, given the large size of
Glossopteris
, it must have been relatively warm.

A strong clue to how this was so is provided by a remarkable living fossil, the Chinese deciduous tree ginkgo, or
Ginkgo biloba
. Fossils of this plant have been found in Antarctic rocks dating back to the Cretaceous period, some one hundred million years ago. Although this was after the time of
Glossopteris,
we know greenhouse gas levels were at similarly high levels. Concentrations of air-breathing stomata on fossil leaves provide a first-order estimate of the amount of carbon dioxide in the atmosphere. The greater the concentration of gas, the more efficiently the plant photosynthesises and the fewer stomata it needs. By nourishing the plants at different levels of carbon dioxide the relationship can be quantified, and the results make fascinating reading. Compared to today's level of 396 parts per million and rising, estimates for the time ginkgo was flourishing in Antarctica suggest it was around eight hundred parts per million. The Earth was in the grip of an extreme greenhouse effect.

The corresponding high temperatures meant there were no icecaps. Instead, the landscape was dominated by rainforest and inhabited by a wealth of wildlife. By growing ginkgo seedlings in blacked-out greenhouses with high levels of carbon dioxide, scientists at the University of Sheffield, in England, have been able to test whether the tree was capable of withstanding complete darkness for months on end. Although the ginkgo plants used up precious food reserves during winter, they could more than compensate for this by photosynthesising during the twenty-four hours of summer daylight. So long as carbon dioxide levels remained high, the forests of Antarctica could not only survive in the dark but thrive.

With the ceaseless shuffling of plates on the surface, Gondwanaland's time was limited. Huge flows of lavas dating back to the Jurassic period are preserved within the Transantarctic Mountains, testament to the massive forces Alfred Wegener envisaged. By the late Cretaceous, some eighty million years ago, the last hanger-on, New Zealand, finally split from the West Antarctic. The supercontinent was no more. The rifting continues today: the Mount Erebus volcano in the Ross Sea is a visible sign of the process that began all those years ago. Satellite data collected since the 1980s shows how perceptive Wegener was. The crust still carries the physical scarring that marks the break-up of Gondwanaland, and the links between Antarctica and the other southern continents. It is a spectacular confirmation of the German's idea of a ‘flight from the poles'.

The end of Gondwanaland had global repercussions. The opening up of the Drake Passage and Scotia Sea around thirty million years ago brought one of the world's great ocean currents, the Antarctic Circumpolar Current, into being. Although this Antarctic current sustains abundant life in the Southern Ocean—including South Georgia and other subantarctic islands—it isolated the southern continent from the rest of the planet. Temperatures in Antarctica dropped precipitously and the vast ice sheets we see today began to grow. With the accompanying cooling there were massive evolutionary changes. For those left behind on the keystone continent of Gondwanaland, the future would prove considerably challenging.