Weekend Argus (Saturday Edition)
Fundamental changes shape our world
One of the most ancient forces of history is the most overlooked, geologist John Rogers tells MICHAEL MORRIS
MORE than a century and a half ago, a man who became a giant of science and whose ideas and theories changed how the world viewed itself, paid a visit to what later became the Sea Point beachfront to cast his eye over a telling rock formation.
This visitor later wrote: “A man must for years examine… great piles of superimposed strata and watch the sea at work grinding down old rocks and making fresh sediment, before he can hope to comprehend anything about the lapse of time, the monuments of which we see around us.” His name was Charles Darwin. We might wonder whether his impressions from that 1836 visit to the Cape and his first-hand observation of the notable reef off Sea Point flitted across his mind as he penned his famous and enduringly controversial masterwork, On the Origin of Species, published in 1859.
The great man’s visit is at least memorialised in a plaque on the Sea Point Promenade, just below the President Hotel, from which a visitor today – just as at any point in many centuries past – can look down on what is obliquely, but meaningfully all the same, called the “Sea Point Contact”.
It describes a dramatic event somewhere between 560 million and 540 million years ago – when magma (or molten rock, which became Cape granite) intruded into the older sedimentary rock of what is called the Malmesbury Group.
The Sea Point Contact is a window on the past and a vivid token of the constant geological change that made – and continues to make – the world.
What distresses retired UCT geoscientist John Rogers is that so few people know much about it, a deficiency he is devoting much time and the expertise of a lifetime in the field to correct.
It comes as no surprise that Rogers defines his childhood hinterland of Northamptonshire, in the UK, by its distinctive Jurassic oolite geology, many of the buildings of the region having been fashioned from this stone. However, his affection for the discipline grew not from an early familiarity with 150-millionyear-old sediments, but an accident of circumstance.
It was when the family was preparing to emigrate to South Africa (to Kroonstad) in 1960, that a chance remark by his father to an embassy official in London – that his son, John, was keen on geology – directed the young Rogers into the world of rocks. A scholarship to UCT cemented a long association with the university, at which he completed four degrees, culminating in a doctorate and followed by many years of teaching and research across southern Africa, much of it offshore.
Since his retirement in 2009, he has remained as vigorously engaged as ever – and chiefly in stimulating enthusiasm for geological knowledge.
“This should be part of our general knowledge,” he said this week – a day before the latest of many trips in his researching life up Table Mountain, with a Japanese television crew.
In a world in which 1996, never mind 1836, might seem an age away, it is difficult to comprehend the extent of geological time – Table Mountain’s venerable age of 520 million years at its base, and 400 million at the top, and all this quite young against the Earth’s age of 4 550 million years.
Darwin was among the 19th century scientists to appreciate the importance of geological evidence in making sense of the world and on his visit to the Cape he met another, the astronomer John Herschel (later Sir John, after whom the school is named) who came to southern Africa to map the stars of the southern sky as his astronomer father, William, had done for the northern sky.
The then 27-year-old Darwin was not overly impressed by the Cape, though it’s possible that by the time of the victualling stop at Simon’s Town from May 31 to June 18, 1836 at the tail end of his five-year voyage on the survey barque, HMS Beagle, he was thinking more of getting home than anything else.
The voyage had already taken in extensive surveys of the Cape Verde Islands, Brazil, Argentina, the Falkland Islands, Chile, the Galapagos Islands, Australia and Mauritius.
Still, while at the Cape, with Scottish surgeon, naturalist and zoologist Andrew Smith (the inaugural superintendent of the South African Museum of Natural History) as his guide, he visited and sampled the Sea Point Contact. He also undertook a trip on horseback to Houw Hoek, Franschhoek and Paarl.
It was possibly his meeting Herschel that was the most significant encounter of the visit.
Stellenbosch academic Wilhelm S Barnard has written that the Beagle “dropped anchor just as Darwin’s thoughts were turning from observation and description to explanation” and that being at the Cape just then “might have played a more important role in the development of his ideas than most commentators have considered”.
Earlier in the voyage, Darwin had written to his sister Caroline of the difficulty of converting description into reasoning.
Barnard observes: “At a critical stage of Darwin’s thinking, Herschel reminded him, perhaps indirectly, that the best way to establish a proper connection among facts was by explanation and that a true cause should be able to explain both granite landforms and the diversity of fynbos bulbs.”
More than a century after Darwin, and working in the discipline of history, Robert Ross turned to the rocks of South Africa to say some important things about the landscape’s youngest events.
In the opening chapter of his 1999 A Concise History of South Africa, the second sentence is portentous and brief in saying this about South Africa: “It is old geologically.”
Ross goes on to explain how geology shaped climate (which shaped settlement patterns and frontiers of conflict) and endowed the landscape with the minerals that were fought over and exploited, sponsoring modern South Africa’s industrial capitalist economy and much of the complexity of its social and economic relations and its world standing.
Here is a sense of Darwin’s conviction that understanding the rocks and stones at our feet or that form the mountains that only seem inert and unyielding is vital to understanding “anything about the lapse of time”. Geology is central to our condition. At the height of summer especially, it is difficult to picture Table Mountain smothered by glacial ice, yet it once was and John Rogers, as a young student in the 1960s, picked up a stone on the top of the mountain which “proved” it.
The pebble, flattened on one side and scored on the other under the pressure of gritty ice millions of years ago, is a lasting token of the slow but profoundly influential force of geological action.
For more information on the Cape’s geology, go to the Western Cape brand of the Geological Society of South Africa’s website at https://sites.google.com/site/gssawcb/