Supercontinent: 10 Billion Years In The Life Of Our Planet

by Ted Nield

  The processes of plate movement are not smooth at our human timescale; the heat engine of the Earth is no perfectly oiled machine. So while the average rate of convergence between South-East Asia and the floor of the Indian Ocean may be 5.2 centimetres per year, unlike your growing toenails, these figures represent the averages of many sudden discrete movements, some of which, especially when long delayed, can be very large and very sudden indeed.

  On 26 December 2004 stress that had built up over hundreds, perhaps thousands, of years was finally released along a 1200-kilometre stretch of plate boundary to the north-west of Simeulue. This stupendous quantity of energy, stored as though in a giant leaf-spring, was liberated in seconds as the crust of the overriding plate (which had been bent downwards by the pressure of the sinking ocean floor beneath) bounced back, flinging the ocean up by as much as ten metres.

  At a magnitude of 9.3 (on a scale whose every increment denotes a quake thirty times larger than the one below), this was the largest quake unleashed by the Earth for half a century, the second strongest ever recorded, and the first true ‘Global Geophysical Event’ since Krakatoa erupted in 1883. Its seismic waves, travelling quickly through the Earth’s crust, crossed the Indian Ocean and passed through the Vivekananda Memorial almost instantaneously, as the whole planet reverberated like a bell struck with a massive hammer.

  The Sumatra subduction system, showing the dates of known historical earthquakes and the sections that moved during each. First published in Geoscientist 15, 8 p. 4. Reproduced courtesy of Dr John Milsom.

  The tsunami meanwhile rolled outwards from where the ocean floor had been uplifted. In deep water, travelling at the speed of a jumbo jet, its waves were only a few centimetres high, passing unnoticed beneath the hulls of container ships crossing the Bay of Bengal, stacked and sleeping in the morning light. But in the shallows, the waves slowed and bunched together, piling up huge cliffs of surging, turbid water that rushed inland like supercharged high tides, sometimes tens of metres tall, razing all before them, scouring the coastline of an entire ocean.

  Rescue

  The tourists and pilgrims, now disembarked at the Vivekananda Memorial, watched as the horror unfolded. The morning was calm and the sky clear and blue. The first thing the visitors noticed was the withdrawing roar of a false tide, as though someone had pulled a plug on the ocean. Dark, wet rocks at the foot of the many islets, and finally the seabed in between, were suddenly exposed. It was as though the sea had inhaled. In the eerie quiet, which had almost silenced the chatter on the Memorial, the visitors could hear the hiss of air being sucked into the pore spaces of the draining sand and the flapping of a few stranded fish. Then, just as the onlookers had begun to shrug their shoulders at the sight, a series of huge waves, each several metres high, rushed in, crashing over the sunstruck promenades surrounding the Vivekananda Memorial. The great statue of Tiru Valluvar was engulfed in spray, like a deep-sea light breasting an Atlantic storm, but on a cloudless morning.

  How many of the visitors to that tiny outcrop of charnockite thought at that moment about Katalakōl, of the lost books, and the palaces of the great scholar kings who, in the dreamtime of Tamil myth, held benevolent sway over the lost lands of Ilemuriakkantam? Perhaps many thanked the gods, because they had indeed made a life-saving choice that morning. All three boats of the Poompuhar Shipping Corporation were washed ashore by the tsunami; but after a long wait all the visitors were rescued, not by the Indian Air Force helicopter, which found it could not land, but by local fishermen whose boats survived the tsunami and who made several sorties to pluck the visitors to safety.

  Over the days and weeks that followed, many stories emerged about how, here and there around the ocean, a little learning had been a life-saving thing; tales of the teacher who saw the tide go out unexpectedly and shooed all her pupils upstairs just in time. They served to show the life-saving power of knowledge; knowledge that most simply didn’t have. But it became clear that, given the right combination of technology and education, many might have enjoyed a fate like that of the lucky fishermen of Nallavadu, on India’s eastern coast.

  The story goes that the son of one Nallavadu fishing family was on holiday in Singapore when he saw a news report of a massive earthquake and rumours of a terrible wave. He telephoned his sister and told her to spread the word and leave home immediately for high ground. This small community had for several years benefited from the presence of a small Internet-linked communications centre, set up by the M. S. Swaminathan Research Centre in Chennai to provide information to fishermen about weather in the Bay of Bengal. Armed with the news, villagers broke into the centre’s telecoms facility and, using its public-address system, told the village’s 500 families to run for their lives. And in the end, not one life was lost from Nallavadu’s population of 3500; though 150 houses and 200 boats were reduced to rubble and matchwood.

  For scientists, especially those working at the Pacific Tsunami Warning Centre in Hawaii, the unfolding situation was immensely frustrating. Together with seismologists all over the world, they had detected the massive quake and knew that a tsunami was a likely consequence. But there is no regular correlation between earthquake magnitude and tsunamis; and without any tsunami sensors in the Indian Ocean, still less any established lines of communication with the countries bordering it, it was impossible for them to get any warning to those who might have benefited (except, finally, to the Horn of Africa, where casualties were low as a result).

  But it was not long before the political will arising from the disaster began to take effect. On Monday 10 October 2005 a German research vessel set sail from Jakarta to place the first of fifteen earthquake sensors on the seabed some 620 miles offshore. Attached by ties to large buoys at surface, their signals are now being continuously beamed to the offices of Indonesian government geologists, and warnings can be relayed to the media and the public via SMS, fax and email. For its part, India decided to set up a tsunami warning centre in Hyderabad at an estimated cost of $27 million, and by December 2005 an interim Indian Ocean tsunami early-warning system costing $53 million, tying together seabed earthquake sensors and tide gauges, was nearing completion thanks to the United Nations Intergovernmental Oceanographic Commission (IOC).

  As usual, because such warning systems involve links at all levels stretching from international to local, coordination will be the biggest problem. Emergency preparedness planning, awareness campaigns, drills and local evacuation plans, educational programmes, and installing emergency operational capability – all these need to be present across a vast area that pays no heed to national boundaries. But without these things, none of the new technology will prove to be any use at all.

  Useful knowledge

  Science historian Naomi Oreskes has written: ‘Scientists are interested in truth. They want to know how the world really is, and they want to use that knowledge to do things in the world.’ It was this same impulse that drove Eduard Suess to design and build his clean-water scheme for Vienna, or Henno Martin and Hermann Korn to find water for Namibia, or John Joly to apply radiotherapy to the treatment of cancer.

  Earth scientists often complain, with reason, that politicians underuse the full potential of their subject, especially for the benefit of vulnerable (for which read ‘poor’) people living in unsafe housing in unstable places. But, in times like the tsunami’s aftermath, this feeling rises to a pitch higher than mere frustration. That feeling is despair: that the world is still so ruled by the short-term, by superstition, inertia and irrationality, and that their humane, possibilist long-term view of the world is not only ignored but even denied.

  If today there is fresh water on Namibian farms and in Vienna, and an emerging tsunami early-warning system in the Indian Ocean, it is because geologists in the past have done the science that brings a closer understanding of deep time and the inner workings of the Earth. You cannot pick and choose with science. A seemingly rarefied geology that reconstructs the lost supercontinents of Earth�
��s deep past is the same science that (with political will) can save hundreds of thousands of lives in the Indian Ocean when the next tsunami strikes. The arcane business of how our Earth’s atmosphere evolved during the Precambrian under the influence of evolving life is the same science that now helps us understand the massive, uncontrolled climate experiment in which the human race is currently engaged. But to deny one part of science is to deny it all. Science hangs together. It is a supercontinent.

  It is also progressive, as its ideas approach ever more closely the actual truth of nature as revealed in the great palimpsest of the geological record. ‘Progress’ may be an unfashionable Enlightenment notion, but in science it is real; and the test of that progress’s reality is the ever-increasing power that science puts in our hands. Just as the history of the Earth is made up of both repetitive cycles and directional arrows, as the wheels of science turn, throwing up the same ideas time and again throughout intellectual history, the train to which they are fixed moves forward.

  When thy judgments are in the Earth

  Therefore how grotesque was it to read, just seven days after the tsunami struck, in the Sunday Telegraph, whose front pages were given over to detailed geological explanations of the earthquake and tsunami, of a new folly being made ready for its first visitors in Petersburg, Kentucky, USA. Called the Museum of Creation and costing about the same as Hyderabad’s tsunami early-warning centre, the theme of this particular park is the literal truth of the Old Testament creation myth, which it seeks to uphold against all (genuine) scientific evidence. Just as the Tamil devotees appeal to outmoded nineteenth-century science to bolster the idea that their national myth is literally true, here the Old Testament creation story is bolstered by what the museum’s backers call ‘creation science’.

  This non-subject, devised by young-Earth creationists to lend credibility to their prejudices, is alas much more than some regrettable but harmless local dispute about the romantic tales of ancient poets. Overenthusiastic appeals by Tamil politicians to a few outdated science references may occasionally be embarrassing for their academics; but it remains, at most, a little local difficulty. On the other hand, the purpose of ‘creation science’ is to misrepresent real knowledge in a crusade to replace free enquiry with slavish adherence to simplistic dogma – with belief in the Word before the world.

  I have tried in this book to show something of how ideas in science often grade into – perhaps even sometimes derive from – ideas in myth, and I have done this to show how important it is to know the difference between the two. The truth is that we, as a species, can no longer afford the luxury of irrationality and prejudice. We are too many and too powerful to live in dreams. And the greatest and most irrational of the prejudices from which we must free ourselves is one identified by Lucretius in the last century BC: the belief that the world was made for us.

  The supercontinent story tells us, like no other in Earth science, that she was not made for us – any more than she was made for the trilobites that grubbed around in vanished Iapetus, or for the Glossopteris tree or the little Mesosaurus, whose fossils reunited Gondwanaland, or the tiny feeding-trace Oldhamia, on whom John Joly mused. Douglas Adams picked up this theme in what I call his ‘parable of the puddle’:

  … imagine a puddle waking up one morning and thinking, ‘This is an interesting hole I find myself in. It fits me staggeringly well; must have been made to have me in it!’ This is such a powerful idea that as the sun rises in the sky … and the puddle gets smaller and smaller, it’s still frantically hanging onto the notion that everything is going to be all right because this world was built to have him in it; so the moment he disappears catches him rather by surprise. I think this may be something we need to be on the watch-out for …

  We can, if we choose, either fret over our lost futurity or comfort ourselves with the thought that one day our species may shuck its bonds and spread throughout the galaxy; and that our space-going descendants may, millions of years in the future, rediscover our home planet after the greatest racial diaspora of all. Maybe that way, our direct offspring will see the next supercontinent on Earth. But this is a long shot. Until we can live without her, Earth is not a part of our story – we are a part of hers.

  As the poet Hugh MacDiarmid put it:

  What happens to us

  Is irrelevant to the world’s geology

  But what happens to the world’s geology

  Is not irrelevant to us.

  The last dethronement

  Science has been trying to humble the hubris of humans from the start, in a series of what Sigmund Freud referred to as ‘dethronements’. The first dethronement was of the Earth as the centre of the universe. Second was our own dethronement as a unique creation in the image of God. Third (in Freud’s opinion) was his demystification of the human mind’s deepest motivations.

  Science is not often thanked for delivering such slights to our collective ego; though in fact these blows have been nothing like crushing enough. For when, like Douglas Adams’s puddle, we find ourselves standing on the brink of destruction it will be our arrogance, as much as the ignorance on which it feeds, that will prove our undoing.

  Science cannot tell us everything that matters about being human, but it provides us with the only practical knowledge of the natural world in which we have any reason to believe. We know this because it works. But science also teaches us another important lesson – that there is no absolute knowledge of any kind – either about the Earth, or anything else. True, science can put some things past reasonable doubt: organic evolution or the age of the Earth are now well beyond that point. Despite what they may tell you in the Museum of Creation, the likelihood such basic scientific ideas being simply wrong is precisely nil. But the key word here is reasonable. Nothing ever remains beyond unreasonable doubt, especially to the fanatical adherents of outworn creeds who desire only to enslave.

  The discovery of deep time is perhaps the greatest single liberating contribution that Earth science has made to wider culture. Conceiving of a timeframe large enough to encompass many repetitions of a cycle that can span 500 million years or more changes one’s perspectives – especially on how properly to judge the relationship between ourselves and the Earth. As our species becomes more numerous and powerful, our last chance of long-term survival will depend on embracing yet another dethronement. We have to realize that we are the puddle, at the mercy of circumstances, but at least able to figure out how to keep ourselves alive and comfortable if we use the capacities with which evolution has equipped us.

  Lucretius, speculating about the age of the Earth, came to the mistaken conclusion that it was new. For if not, he asked, where were the works of the poets who sang before Homer? Twenty centuries later John Joly wrote in reply:

  We do not ask if other Iliads have perished; or if poets before Homer have vainly sung, becoming a prey to all-consuming time. We move in a greater history, the landmarks of which are not the birth and death of kings and poets, but of species, genera, orders. And we set out these organic events not according to the passing generations of man, but over scores or hundreds of millions of years. We are … in possession today of some of those lost Iliads and Odysseys for which Lucretius looked in vain.

  FURTHER READING

  Books

  Adams, Douglas, 2002. The Salmon of Doubt. Pan. 284pp. Posthumous collection of writings by the renowned author of The Hitchhiker’s Guide to the Galaxy. Contains the ‘parable of the puddle’ in the essay ‘Is there an artificial God?’

  Benton, Michael J., 2003. When Life Nearly Died – The Greatest Mass Extinction of All Time. Thames & Hudson. 336pp. Readable text-book by an acknowledged expert and popularizer, focusing on the end-Permian extinction and possible reasons for it.

  Bronowski, J., 1973. The Ascent of Man. BBC. 448pp. Accessible and authoritative examination of the place of science within the rise of human civilization.

  DeCamp, L. Sprague, 1954 (rev. 1970). Lost Continents: The Atla
ntis Theme in History, Science and Literature. Gnome Press (1954), Dover Publications (1970). 348pp. Spirited account of the influence of Plato’s Atlantis story on subsequent lost-world makers.

  Greene, Mott T., 1982. Geology in the Nineteenth Century: Changing Views of a Changing World. Cornell University Press. 324pp. A classic, well-written analysis of Earth science’s heroic age, including the origins of drift theory.

  Koertge, Noretta (ed.), 1998. A House Built on Sand: Exposing Postmodernist Myths About Science. Oxford University Press. 322pp. A selection of essays by scientists and philosophers that examine postmodern constructions of science and analyse the political damage they inflict upon science in society.

  McMenamin, M., 1998. The Garden of Ediacara: Discovering the First Complex Life. Columbia University Press. 295pp. An idiosyncratic view of how complex life first evolved on the shores of the supercontinent Rodinia.

  Oreskes, Naomi, 1999. The Rejection of Continental Drift – Theory and Method in American Earth Science. Oxford University Press. 420pp. Insightful analysis of the true sociocultural reasons why US scientists found Wegener so hard to swallow.

  Oreskes, Naomi, 2003. Plate tectonics: An Insider’s History of the Modern Theory of the Earth. Westview Press. 424pp. Accounts in their own words by many of the surviving major players in the plate-tectonic revolution.

  Ramaswamy, Sumathi, 2004. The Lost Land of Lemuria: Fabulous Geographies, Catastrophic Histories. University of California Press. 334pp. On the interface between Lemuria, Tamil world history and culture. Superb scholarly study by the noted Tamil cultural historian.