In the expedition report from 1878, the name of the Arctic Ocean has been changed to the Norwegian Sea, because since ‘time immemorial [it] has been traversed by our seamen.’ In the final year of the expedition, DS Vøringen sailed to the far north, to Bear Island and Spitsbergen, where the crew collected fossils, surveyed the land and determined the heights of mountains.
The Norwegian North Sea Expedition gave rise to many scientific books and new maps. One of these books alone, Nordhavets Dybder, Temperatur og Strømninger (North Sea Depths, Temperatures and Currents), contains as many as twenty-seven maps illustrating subsurface temperature and pressure variations, winds and currents, and depths.
FRAM I | Henrik Mohn and Georg Sars wrote that ‘the equipping of a true North Pole Expedition, with the aim of reaching the so-far unexplored Polar Region, is not our duty. We must entrust this to richer nations.’ But fifteen years after DS Vøringen had completed its voyage, a government-funded expedition would set out for the North Pole in a specially constructed ship–the Fram. Sars and Mohn were both involved in the expedition planning, despite their earlier reservations.
In the autumn of 1884, Fridtjof Nansen had read in the Morgenbladet newspaper that the remains of a ship wrecked on the New Siberian Islands had drifted all the way to the coast of Greenland–several thousand kilometres further west. This gave him the idea for a sea voyage across the Arctic Ocean in a boat that drifted with the ice–perhaps the ocean currents would carry him across the promised pole. ‘One of the scientific tasks of the expedition was to investigate the depth of the Polar Sea,’ wrote Nansen in the book Farthest North thirteen years later. Before the expedition set out, the general consensus based on soundings performed in the Barents Sea and other adjacent waters was that the Arctic Ocean was shallow: ‘I presupposed a shallow Polar Sea, the greatest depth known in these regions up till now being 80 fathoms,’ wrote Nansen. Like many others, he presumed that ‘the regions about the Pole had formerly been covered with an extensive tract of land, of which the existing islands are simply the remains.’ He dismissed the idea that land might not also be discovered further north as ‘ridiculous.’
But the first soundings gave surprising results. In March 1894, when the expedition was located at around 80 degrees north, the crew ‘had out 2100 metres (over 1,100 fathoms) of line without reaching the bottom. […] Unfortunately we were not prepared for such great depths, and had not brought any deep-sea sounding apparatus with us.’ The solution was to unravel one of the ship’s steel cables and tie the strands together to create a plumb line almost 5,000 metres long. They finally reached the bottom at 3,850 metres. ‘I do not think we shall talk any more about the shallow Polar Sea, where land may be expected anywhere. We may very possibly drift out into the Atlantic Ocean without having seen a single mountain-top,’ wrote Nansen in his log book. The discovery resulted in all theories of a North Pole continent having to be scrapped. Nevertheless, in 1895 the French newspaper Le Figaro reported that Nansen had planted the Norwegian flag ‘in the mountains’ at the North Pole.
Nansen wrote a pioneering work about the Arctic Ocean floor after the expedition, in which he posited a theory of changes to the Earth’s crust. Based on the soundings he and his crew had completed in the shallow Barents Sea, and their surveys of the surrounding areas of land, Nansen believed that before the great ice ages the Barents Sea had been dry land, through which rivers spread outwards, cutting into the extensive plains–and later research would prove him right.
PING… PING | When the seventh International Geographical Congress was held in Berlin in 1899, mapping of the ocean floor had reached a point where there was a need for common names that could be used on the maps. A commission was established to create a bathymetric map–a map of the ocean floor. Everyone agreed, however, that the first attempt–the Carte générale bathymétrique des oceans (General Bathymetric Chart of the Oceans)–was terrible. A significant technological leap was needed to enable the proper mapping of the ocean’s depths–and this came after the Titanic collided with an iceberg in the year 1912 and 1,513 people consequently drowned. The need for an improved overview and increased safety led to the British taking out the first patent on a sonar system just one month after the Titanic sank.
The sonar system emitted a sound through the water, a so-called ‘ping’, and by measuring the time it took for the sound to return after hitting something below the water’s surface, a single person could do in just a couple of seconds what had previously taken several individuals many hours. The principle was simple–but the challenge was to construct a device that was accurate enough. Sound moves through water four times faster than through air, which means that a half-second delay is equivalent to 1,000 feet. Harvey Hayes, a physicist in the United States Navy, was the first to invent an echo sounder that could be used in deep water. In the summer of 1922, he sailed from Newport to Gibraltar. Over just one week he performed 900 deep-water soundings–far more than HMS Challenger had performed during three and a half years. Hayes’s invention finally made it possible to see the world’s seas and oceans free from water.
From 1925 to 1927, the German vessel Meteor measured the depth of the Atlantic Ocean at an entire 67,388 positions using sonar. Had the crew been forced to lift and lower a plumb line manually, such a survey would have taken seven years with the crew working twenty-four hours a day, seven days a week. The researchers on board were interested in finding out whether it was possible to extract enough gold from the salt water to enable Germany to pay off the debt the country was left with after the First World War. Unfortunately, it wasn’t.
While the German ship sailed up and down the Atlantic Ocean, one day in 1926 a six-year-old girl visited the south-east coast of the USA and saw the ocean for the very first time. Pascagoula, Mississippi, is a flat area where the land lies just a few centimetres above the ocean surface, slipping almost invisibly below it where the trees, grass, bushes and sand all come to an end. What did this six-year-old girl make of the apparently empty surface she saw before her? Did she imagine that the landscape continued somewhere out there below the water, where she was unable to see it? That there were mountains and valleys hidden somewhere out there, too?
The girl’s father worked as a map-maker for the agricultural authorities, and so this period by the water was an exceptional time in her childhood–usually the family were based far inland, somewhere within the great farming states. She took off her shoes, allowing her feet to sink into the sand; feeling the waves wash back and forth across her toes. On the beach was a shipwreck, and the following day, when the tide was high, it was barely visible above the water. Far out at sea, the Meteor revealed that the Mid-Atlantic Ridge was a mountain range, not a plateau as the researchers aboard HMS Challenger had believed, and twenty-six years later this six-year-old on the beach–Marie Tharp–discovered this mountain range was being ripped apart because the Earth’s continents are in a state of constant motion.
DOC | In 1930, American geologist Maurice ‘Doc’ Ewing became a professor at the age of twenty-four. He was an odd character–a large part of his teaching involved taking his students out into the field to blow things up using dynamite. This was illegal, of course–but the time it takes for a seismic pressure wave to return to the Earth’s surface provides information about the types of geological structures present in the ground, and measuring this time delay is an excellent way for anyone wishing to make geological maps to obtain data. One day, Ewing was asked if he wished to study the American continental shelf. At this time, it was known that the ocean suddenly became deeper a couple of nautical miles from land–but nobody knew why. Doc had never worked out at sea before, but, he wrote in his autobiography, ‘if they had asked me to put seismographs on the moon instead of the bottom of the ocean I’d have agreed, I was so desperate for a chance to do research.’ He became the first person to use explosion seismology to map the ocean from the coastline to the end of the continental shelf.
Doc became obsessed wit
h the ocean floor. Attempting to understand the Earth by investigating only the 30 per cent of it that exists above water was, he believed, ‘like trying to describe a football after being given a look at a piece of lacing’–a thought that had never occurred to most other geologists. Nor did oceanographers at the time really understand what Doc was working on. Harald Ulrik Sverdrup, the Norwegian oceanographer who was head of the Scripps Institute of Oceanography from 1936 to 1948, wrote that the ocean floor was primarily only of interest by virtue of its being the place where the water ended, but Doc took a completely opposite view: ‘The ocean is just a murky mist that keeps me from seeing the bottom. To be honest, I wish the whole thing’d just dry up.’
As early as the 1930s, Doc’s surveys showed that the continental shelf mainly consisted of sediments–porous types of rock strewn across the bedrock, which often contained oil and gas. He asked Standard Oil whether they would be open to financing his research, but no–they were not interested in spending as much as five cents on looking for oil out in the ocean.
During the Second World War, the United States Navy contacted Doc–perhaps he could help them find German U-boats using sonar and the world’s first underwater camera, in exchange for funding to develop his latest gizmos. ‘During the war we used to talk about what fun we were going to have afterwards when we took all these instruments that were being developed and started doing science with them,’ said Doc, and this was true–the period that followed the Second World War saw significant growth in oceanographic research. The Atlantic and Pacific Oceans were strategically important locations that separated the world’s two superpowers. Doc became a professor at the recently established Institute of Geophysics at Columbia University in New York, and when a young woman with a prestigious geological education and experience visited him in 1948 to apply for a job, Doc asked her: ‘Can you draft?’
Maps of the Norwegian Continental Shelf from 1965 and 1971 respectively, which show areas assigned for exploratory drilling in the North Sea. The map from 1965, which has been coloured by hand, shows that twenty-two licences were awarded for seventy-eight areas in the first licensing round. The first major oil discovery was made four years later.
THE PG GIRLS | The Second World War had given American women new opportunities. One day in 1942, as Marie Tharp was buzzing around the University of Ohio, unsure whether to continue studying philosophy, music, art, English, German, zoology or palaeobotanics, she saw a poster from the University of Michigan–geology students were guaranteed work in the oil industry after graduation. Tharp had studied a little geology already, as just one of three women out of a year group of seventy-three students. Her grades were nothing spectacular, but Tharp’s lecturer thought she showed promise, and encouraged her to combine the subject with drafting so that she would at the very least be able to work with geology in an office. Taking women out into the field was not something male geologists were in the habit of doing.
Since most of the country’s young men had been sent off to war, it was only natural that most of the geology students would be young women, who in Michigan became known as the ‘PG girls’–the petroleum geology girls. Wearing jeans stuffed into tall hiking boots, they set out on excursions up to the Black Hills, where they studied rocks and drew maps of the terrain. At this time nobody was entirely sure about exactly how the area had been formed. Why were there mountains and valleys? Why was the Earth’s crust not smooth, like a shell?
One of Tharp’s textbooks admitted that ‘the cause of crustal deformation is one of the great mysteries of science and can be discussed only in a speculative way. The lack of definite knowledge on the subject is emphasized by the great diversity and contradictory character of attempted explanations.’ One lecturer at Harvard University had as many as nineteen different explanations as to how mountains were formed. Tharp studied the theory that suggested that the Earth shrank because it cooled after its fiery creation, which resulted in the geography being set in motion, and that of continental drift, through which entire continents changed places. Most geologists dismissed both theories. As for the other theories, the textbook informed her, there were simply too many to include. A significant part of being a geologist was about formulating more or less educated guesses.
As the Second World War was coming to an end, Tharp had completed the four semesters necessary to take a master’s degree in geology, and took a fifth semester of physics, maths and chemistry because she felt she was lacking in these areas. All this cross-disciplinary curiosity unsettled her tutors, who were afraid Tharp would abandon geology. They therefore encouraged her to take a job in an oil company straight after graduation, for which she earned good money, but spent most of her day bored out of her wits–as a general rule women were given work for which they were overqualified. Tharp continued to study mathematics in her free time, and took spherical trigonometry, the science of how things relate to one another on a sphere; useful for anyone wishing to navigate larger distances across the oceans–or, as it would turn out, create a map of them.
Twenty years after she saw the sea for the first time, Tharp would see it again when she moved to New York seeking new challenges, which led her to Columbia University and the Institute for Geophysics. ‘I’m looking for a job’, she said to the institute’s secretary. ‘A job?’–‘Yes. I asked at the geology department upstairs and someone told me a Doctor…’ She checked the note in her hand. ‘… Maurice Ewing might be looking for people.’ The secretary took her along to Doc, who, after hearing Tharp speak about her cartographer father, geology studies and the work she had performed for the oil company, asked her if she could draw.
AN UNEXPECTED RIFT | Marie Tharp’s first geology tutor had been right–women with an interest in geology needed to learn to draw. Tharp informed Doc that she could, and so Doc gave her a job at the institute, where twenty-three people squeezed into three rooms attempted to understand the interactions between the ocean floor, dry land and the atmosphere. Tharp was the sixth woman to be employed at the institute: Midge did the accounts; Jean, a mathematics and physics major, made coffee, typed things up on the typewriter and performed minor administrative tasks; Emily and Faye, both mathematics majors, worked as calculation assistants for one of the male staff; while Marie, with a graduate degree in geology, undergraduate degree in mathematics and additional qualifications in physics and chemistry, was employed to draw copies of maps and make table calculations.
Not long after Tharp was employed, the entire institute moved to new, larger premises beside the Hudson River, a gift from widow Florence Lamont, and changed its name to the Lamont Geological Observatory–a sign that the group was now studying more than geophysics alone.
But the move had no consequences for Tharp’s work and, after four years, she’d had enough. She left for her father’s farm in Ohio, and didn’t return until she received a telegram: ‘Consider this an extended vacation. Doc.’ At the observatory it was decided that Bruce Heezen, a geologist who was both younger and less qualified than Tharp, would be responsible for her work. Their first meeting was described by a German society magazine many years later as follows: ‘… small waist, swinging long skirt, graceful line. She looked very charming. As he came over to her, she felt his warm manhood, the scent of his skin, and his voice was deep when he said: “Marie, we will be cartographers of the whole globe, its topography under the sea. Science will have to accept that.” In this night they became a loving couple that stuck together for the coming lifetime.’ We can only guess at what Tharp might have had to say about the veracity of this account.
What we do know, however, is that Tharp and Heezen collaborated closely until Heezen died of a heart attack in a submarine off Iceland in 1977, and that their work together started when Heezen set the cardboard boxes on Tharp’s desk and asked her whether she could turn their contents into a map.
Tharp started the map by drawing coastlines, lines of latitude and longitude, and then the areas closest to land where centuries of soundings
had provided a certain overview. She then drew the subsea landscape along the six routes that the observatory’s oceanographers had explored using sonar. The result was solid–the best representation of the Atlantic Ocean floor to have been produced to date–but Tharp wasn’t satisfied. She hadn’t discovered anything new. At the same time, however, there was something that gave her pause–the apparent rift in the Mid-Atlantic Ridge. And after Tharp and Heezen’s first argument, which ended with them agreeing to disagree about whether the results suggested continental drift, something curious happened at one of the observatory’s light tables.
At this time, Heezen and a colleague were working with a map on assignment from Bell Laboratories, owned by Western Electric, who made telephone cables, and American Telephone & Telegraph, who used them. The companies were now planning a transatlantic telephone cable. But where would it be best protected against earthquakes? Where was the flattest underwater landscape, so they could use as little cable as possible? In short, where should they lay the cable? The observatory staff were therefore in the process of creating a map that documented where in the Atlantic earthquakes occurred. One day, this map and Tharp’s map–without either Heezen or Tharp being able to remember why–ended up being laid over each other on a light table, and clearly showed that earthquakes had a striking tendency to start exactly where Tharp believed the rift in the Earth’s crust to be located.
Tharp used this new knowledge to make some educated guesses. On a new map, she drew a mountain range that stretched from Greenland in the north, down the southern Atlantic Ocean, around the southern tip of Africa, north-west into the Indian Ocean, where HMS Challenger had found shallow waters between Madagascar and India, and from here west into the mainland to the East African Rift–an area in which the Earth’s crust is moving. She then compared the East African Rift with the subsea rift. They looked the same.
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