An Earth – Shaking Discovery – IELTS Academic Reading Passage

In 1963, a paper appeared in the journal Nature that radically changed the way we view this planet and its resources. Tts authors, Fred Vine and Drummond Matthews, did for the Earth sciences what Crick and Watson did for biology and Einstein did for physics, and new areas of scientific development are still emerging as a result.

Yet both men are largely forgotten and unrecognised. What Vine and Matthews did was to provide proof that continents really do drift across the surface of the globe. This understanding profoundly affects the way we use the planet today – it directs the way we prospect for resources such as oil and minerals: it has enabled us to predict most volcanic eruptions and to understand patterns of earthquakes. Incredibly perhaps, an understanding of the mobile dynamic nature of the Earth is helping an understanding of long-term global climate changes. Despite the significance of their work, neither man received great honour or fame.

The idea of continental drift was first proposed in a serious way by the German meteorologist Allred Wegener in 1915. People had noticed the neat jigsaw-like fit between South America and Africa, but Wegener found actual fossil evidence that the two continents were once joined. No one took him seriously; in fact he was ridiculed by most of the geological community. This was partly because, not being a geologist, he was perceived as an outsider. But the main reason for the hostility; according to Vine, was that Wegener was unable to come up with an explanation as to how whole continents could possibly move even an inch, let alone dance to the music of time around the globe.

In the 1920s, the Scottish geologist Arthur Holmes hypothesised that convection currents within the Earth ‘could become sufficiently vigorous to drag the two halves of the original continent apart! In the late 1950s, an American, Harry Hess, came up with the hypothesis that new sea floor is constantly being generated at the mid­-ocean ridges by hot material rising in a convection current. But neither man could find evidence to prove it. It was no more than just a hunch that it had to be right, and a hunch is not enough for science.

Vine had been fascinated by the apparent fit of the continents since the age of 14, and as a graduate student at Cambridge was assigned a project analysing one of the new magnetic surveys of the ocean floor. He found what he describes as parallel zebra swipes of normal and reversed magnetism’ around the mid-ocean ridge. Most significantly; these stripes were symmetrical either side of the ridge crests. There had to be a reason for this. The young Vine and his supervisor Matthews proposed that the magnetic stripes were caused by new ocean floor being formed as molten rock rose at the mid-ocean ridges and spread each side of the ridge.

As the molten rock solidified, it became weakly magnetised parallel to the Earth’s magnetic field. U was just becoming recognised in the early 1960s that the Earths magnetic field flips every so often, so magnetic north becomes a magnetic south pole and vice versa. These flips in magnetic field were being recorded in the new sea floor. It was like a giant tape recording of the ocean floor’s history. As new sea floor was made, it pushed the last lot aside, widening the ocean and in turn pushing the continents either side further apart. In other words, they had discovered the mechanism driving drifting continents that was missing from Wegener’s work. The science of the Earth was never the same again.

By the end of the 1960s, confirmation of global sea floor spreading led to plate tectonics – the view of the outside of the Earth comprising just a few rigid plates which are shunted about by growing sea floor. There was a realisation that mountains are formed when two plates collide, and that most volcanoes and earthquakes occur on the edges of these plates. All this was accepted as fact by all but a few diehard dinosaurs in the geological world.

It is now in the impact of shifting continents on the global environment that Vine feels the most exciting and significant research lies: ‘The distribution of continents and the opening and closing of ocean gates between continents has had a profound effect on climates and has caused flips from Ice­house Earth to Green-house Earth.’ The recognition that the Earth’s hydrosphere, atmosphere and biosphere are all intimately linked with the drifting continents and the goings- on deep within the Earth has spawned the term ‘Earth Systems Science’. It is a great oak tree of science that has grown from the acorn of truth supplied by Vine and Matthews. The holistic approach of earth systems science is very much welcomed by Vine: Tm rather pleased that this has come together.’ He feels that the future for understanding the planet lies in an integrated approach to the sciences, rather than the isolated stance the geologists took throughout the 20th century: There was an incredible polarisation of science and I was caught between the boundaries. It was anathema to me – the whole of environmental science should be integrated.’

Questions 14-17
Complete each sentence with the correct ending A-G from the box below.

14. The work done by Vine and Matthews has had implications concerning
15. Wegener attempted to provide an explanation of
16. Wegener’s conclusions were greeted as
17. The theories presented by both Holmes and Hess concerned

A matters that had not received much attention for some time.
B something which could not possibly be true.
C something misunderstood at first but later seen as a breakthrough.
D matters beyond simply the movement of continents.
E something that had already been observed.
F something arrived at by intuition that could not be demonstrated.
G matters requiring different research techniques

Questions 18-22
Label the diagram below.


Questions 23-26
Answer the questions below using NO MORE THAN THREE WORDS for each answer.

23. What is the name of the theory concerning the structure of the Earth that developed from the demonstration of sea floor spreading?
24. According to Vine, what has the movement of continents had a big influence on?
25. What branch of science has emerged as a result of the work done by Vine and Matthews?
26. Which word does Vine use to describe the way in which he believes study of the Earth should be conducted?

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