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The Age of the Earth - Episode 2

Firmly entrenched and supported by the church, Ussher’s date seemed impregnable. However, some sceptics put forward their own versions. A French Calvinist and lawyer, La Peyrere in 1641 postulated that there had been people on Earth before Adam. This was heresy and of course was banned by Cardinal Richelieu, the prime minister of France. Essentially a pragmatic and fair man, he however realised what effect La Peyrereses manuscript might have in France. La Peyrere kep this freedom, but he did not desist with his theories, eventually in 1655 invoking the wrath of the Catholic Church. He was arrested, interred and forced to recant his heretical views – in short he got off lightly. Enter another player on this grand stage – a Jesuit missionary, Farther Martino Martini, who was carrying out missionary work in China.

Martino Martini

On telling the Chinese that mankind had been destroyed by God in a great deluge, they greeted his pronouncements with great hilarity and disbelief. Their own history stretched well beyond the so-called date of the Flood, and they had records to prove it. A reversal of roles took place, with Martini realising that the ancient Chinese chronology posed a serious challenge to the authority of the bible. In 1654 he returned to Europe, where he published an account of Chinese history, receiving of course the usual disbelief and hostility which marked all other controversial ideas perpetuated at the time. However arrest and persecution was out of the question as Martini had returned to China to further his missionary work. Europe continued her dyed-in-the-wool approach, but slowly thinking was evolving, with crucial intellectual shift away from biblical textual authority towards an enquiry based on scientific principles. Throughout Europe the cry was the same: rocks, not books were believed to hold the secrets of the past. And indeed they did, and still do, and it was left to the natural philosophers to prove the age of the world.

One of the more interesting notions of the 17th Century was that the Earth had been created fully formed; flat, beautiful, unblemished, with no disease, famine, mountains or deserts to blemish her perfect face. A golden age had existed before the Flood, and age when all God’s blessings were poured out onto the world – in short a perfect God had created a perfect world. But now things were in decline – the Earth had become old and wrinkled, volcanoes and deserts were carbuncles and scars on the face of the Earth. An old prophecy that the world would last only 6000 years was being confirmed by nature. The thinking was that the Earth had run most of its days, and doomsday was not far off, perhaps only 350 years in the future (taking of course the date of 4004 BC as the day of creation).

However this idea of an ageing Earth brought the notion of a world in flux and a constant state of change to the fore, and it was Rene Descartes who lead the break with the literal interpretation of the bible. Reason was the reason de etre. Paris, 1625, and our clever and sociable Descartes had become the leading light of Parisian intellectual life – a time when libertine free thinkers were making their mark. Caution was always necessary and a weather eye was kept open for gathering storm clouds in the direction or Rome. One Giulio Vanini, a ‘heretic’ doctor, had had his tongue cut out before being strangled and burned six years before for voicing some anti religious views. Inevitably the storm broke and Descartes moved to Holland, a country which has always had a tradition of tolerance and liberalism which endures to this day. He began his philosophical treatise, The World, which was to be a completer revision of philosophy which he eventually published in 1641.

Rene Descartes

However it was a watered-down version of his original manuscript as it was a bad time for liberal thinkers. Galileo had recently been arrested and forced to recant his heretical views that the Earth went around the Sun. Descartes’ view of the world was essentially that a few simple laws governed the universe, and these laws were what created the complex world around us. The world had the same relationship to God as a clock had to the clock maker – once it had been carefully constructed and set in motion, there was little more involvement from the creator. His ultimate achievement was to remove God from the day to day running of the world. Until then the belief was that God was intimately involved in the day to day, minute to minute running of the world. God may have created the world, but it was then governed by the laws of nature.

To be continued.......................

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The Origins of the Science of Geology

Romancing the Stone

Humankind has had an intimate association with the Earth from the first tentative footsteps of those early hominids to our current insatiable need for minerals and fossil fuels. Undoubtedly our early ancestors were aware of geological deposits, whether they were a source of flint for hand tools or clay for cave paintings or body adornment. Once the origins of the science stretch way back into the early history of man. Adobe to build dwellings or the source of ochre for cave paintings may have been the first venture into sources of materials for the use of mankind. Later stones and clay would have become important as building materials or for brick making. Certainly the ancient Egyptians were using bricks in their less ambitious constructions. And to deny that there was no understanding of the local geology when it came to the quarrying of stone for the Egyptian pyramids would have been naive indeed.

Herodotus, 484 to 426 BC, made many significant geological observations, speculating about the effect of earthquakes on landscapes, but ascribed their causes to Poseidon. Pliny the Elder (AD 23 to 79) lost his life tramping around the slopes of Vesuvius during the eruption that destroyed Pompeii. His reasoning was that earthquakes were a result of Earth’s resentment against those that mutilated and plundered her for gain. Christianity put scientific enquiry literally into the dark ages due to an all encompassing theory for the cause of everything, and besides it was thought that the Earth was a very young place, doomsday was nigh, and therefore the study of the machinations of the planet would be a pointless exercise. Inconsiderately doomsday did not arrive which got some individuals wondering about the natural world. In addition the increasing preoccupation during the Middle Ages with alchemy kick started a scientific process which continues to this day. Leonardo da Vinci, Nicholas Copernicus, Galileo Galilei, brave and brilliant philosophers and scientists all, drove some of the first nails into the coffin of ignorance, holding high the light of knowledge for those who would see.

However the first real attempt on a treatise on geology was made by Scottish farmer James Hutton in an inaccessible 1795 tome titled ‘A Theory of the Earth with Proofs and Illustrations.’ He might have passed into geological obscurity if it wasn’t for a certain John Playfair who rewrote the book on Hutton’s death, making it possible for mere mortals to grasp the concepts that Hutton had so obscurely written about. At that time natural philosophers were divided into two camps – the Neptunists, who believed that everything on Earth, including sea shells on lofty peaks, were due to rising and falling sea levels, and the Plutonists, who noted that volcanoes and earthquakes continually changed the face of the planet and that seas were not the agents which the Neptunists believed. Plutonists also raised difficult questions such to the whereabouts of all the water during periods of tranquillity, a period we are experiencing now.

Hutton’s insights threw some light on the matter, thanks to his keen eye and a close identification with the land thanks to his farming background. He observed the formation of soils, and their erosion and transport to other locales. He realised that over time this erosion of the high ground and the infilling of the lows would leave a planet smooth and devoid of topography. However everywhere he looked there were hills and mountains, particularly so in his native Scotland. He realised that there had to be some process that renewed and uplifted the landscape the keep the cycle going. Those pesky fossils on the mountain tops had not been deposited by floods, but had been lifted there, along with the mountains themselves. Heat within the Earth was the driving force of all this activity, or so ran the thoughts of Mr Hutton. Interestingly some of these thoughts have only been vindicated in the last 40 years or so. More importantly however was the idea that these processes required immense periods of time – far more than anyone had as yet ever conceived.



At the same time, down south, William Smith was building canals and draining bogs for a range of clients as part of the expanding infrastructure driven by the Industrial Revolution. During his daily work he uncovered a myriad of fossils, and realised that each succeeding geological bed or formation had its own particular assemblage of preserved organisms. Spending huge amounts of time and money, he travelled widely across vast swathes of England and to some extent Scotland, mapping the various outcrops of the various strata wherever he went. His exertions damaged his health had his finances to the extent that he even spent time in a debtors gaol, and perhaps even more galling for him, his work was discounted and ridiculed by the supercilious aristocrats who had formed the Geological Society of London in 1807.


However an examination of the map that Smith produced and now hangs in the Society’s headquarters in London reveals his genius. His map shows in amazingly accurate detail the geology of the British Isles and was the first ever geological map. Singlehandedly Smith had mapped out what the British Geological Survey, with hordes of geologists and government funding, couldn’t really improve on except by adding detail. And in a true Hollywood ending, Smith was eventually accepted and then lauded by the Society, and was granted a pension in his latter years, putting off forever the spectre of a debtor's prison and a difficult retirement.


Charles Lyell then enters the stage. He had managed to wade through chunks of Hutton’s book, and was eternally grateful to Playfair for rewriting the work into something approaching readable. Lyell was the most influential geologist of his century, which was a time incidentally when the world was in thrall to all things geological. Geology was the central science and the older Royal Society was in danger of being eclipsed by the upstart Geological Society as the premier scientific society of the country, which at that time also meant the world. So popular was the science that when Charles Lyell travelled to America to lecture, 3000 people showed up to be enlightened on ponderous subjects such as marine zeolites and seismic perturbations in Campania. Back home, modern, thinking men would venture forth to do fieldwork dressed in top hats and dark suits, except for a Reverend Buckland of Oxford who preferred an academic gown. Lyell produced his masterpiece, The Principles of Geology, which built on the works of Hutton of a previous century and made his reputation. Charles Darwin carried a copy of his book on the Beagle voyage, writing afterwards “the greatest merit of the Principles was that it altered the whole tone of one’s mind, and therefore that, when seeing a thing never seen by Lyell, one yet saw it partially through his eyes.”

Between the time of Hutton and Lyell there arose another controversy that followed on from the great Neptunist-Plutonist debate. New lines were drawn between the Catastrophism and Uniformitarianism camps. The former adhered to the idea that the Earth was shaped by cataclysmic events – floods, mainly, while the latter camp believed that changes on Earth took place over immense periods of time. The Catastrophists found that their theory worked in well with the Noachian deluge and therefore did not fly in the face of any biblical beliefs. Lyell was a Uniformitarian and his influence remains right down to the present day. As an interesting aside however, rude Catastrophist brickbats still whizz down the passage of 2 centuries to strike at the very heart of Uniformitarian belief. These brickbats comprise meteorite impacts which are widely believed to have brought to a close the Cretaceous Period and the demise of the dinosaurs, and have been invoked as the cause of a number of other extinctions in Earth history.

Because the Brits were the most active in the early years of the science, British names were assigned to the geological time scale. The Devonian Period is named after Devon, the Cambrian after the Roman name for Wales, and the Ordovician and Silurian after ancient Welsh tribes, the Ordovices and the Silures. However other names began to creep in from practitioners elsewhere – Jurassic from the Jura Mountains of southern France, Permian from the Russian province of Perm while the Cretaceous was named by a certain J.J. d’Omalius d’ Halloy of Belgium.

Initially the geological time scale was divided into 4 spans – Primary, Secondary, Tertiary and Quaternary. The Tertiary is the last surviving member of this initial subdivision, although Quaternary does get a period outing. Lyell introduced additional units known as epochs or series to cover the period since the end of the Cretaceous. These were the Pleistocene, meaning ‘most recent’ Pliocene, the ‘more recent’, Miocene, ‘moderately recent’ and Oligocene ‘but a little recent.’ Nowadays geological time is divided into four great chunks known as eras – Precambrian, Palaeozoic, Mesozoic and Cainozoic, which in turn are divided into Periods which some of you may be familiar with, viz., Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, and Cretaceous. (Camels Often Sit Down Carefully Perhaps Their Joints Creak is a useful acronym for remembering them).

Romancing the Stone

Romancing the Stone

From Hilton’s lofty viewpoint one can almost imagine the blue smudge that is the Indian Ocean out towards the east, particularly after rain when the visibility is at its best. I often marvel at the amazing altitude difference between the City and the misty heights and how comfortable we are with the 500 m ascent which many of us make on a daily basis. This may be partly due to a long and familiar association with this ‘Hill’ which defines to some extent our town and which we effortlessly beetle up and down thanks to the internal combustion engine. However there is more to all this than initially meets the eye and it is an interesting but fairly obscure fact that the African hinterland, and Southern Africa in particular, has an average altitude of 1000 m. This is significantly higher than areas underlain by similar geology elsewhere on Earth, where average elevations of 300 m are the norm. Consider too that the highest point in Southern Africa, Thaba Ntlenyane, is located approximately 160 km from the coast. The descent from Southern Africa’s highest point to the littoral is therefore abrupt – from 3300 m to sea level over a horizontal distance of 160 km – this is nothing less than phenomenal and is almost unheard of except in very mountainous terrains. Question is, why? Current thinking has it that Southern Africa is elevated due to ongoing mantle-plume activity beneath the subcontinent which initiated the break-up of the supercontinent of Gondwana approximately 160 million years ago. In lay person’s terms, this ‘hot spot’ beneath the Earth’s crust has led to a localised upwelling of buoyant, molten material (the mantle plume) which in turn has led to upward bulging of the overlying crust and associated elevated topography. Ongoing tensional stresses in the Earth’s crust due to continental rifting led to the formation of seaways (the infant Indian and Atlantic Oceans) on the Southern African continental margins. This resulted in faulting and the stepping down of the landscape from the original land surface of the interior (what is now the highland regions of the Drakensberg) to the ocean margins.

As our Dusi paddlers can attest, the Umsundusi and Umgeni Rivers flow through some spectacular, steep-sided valleys and the same can be said for the rest of the rivers of the province – Umkomaas, Umzimkulu, Umhlatuze and the great granddaddy of them all, the Thukela. The existing rivers, originally flowing on a high altitude plain prior to Gondwana breakup, then took the most direct route to the newly formed Indian Ocean, cutting down through the ancient bedrock to the sea to form the spectacular kloofs and valleys which we know so well. The verdant growth of Strelitzia and Acacia and the unique ecosystems of these valleys are a direct result of this remarkable geological event. From the lofty viewpoint atop Town Hill one gets some inkling of the spectacular scenery of the Umsundusi and Umgeni Valleys, but for some real mind-blowing scenery, follow the Comrades Marathon route to Durban and keep your eyes peeled for views of the Valley of a Thousand Hills out towards the east. Perhaps even more spectacular vistas are to be had on the road from Hillcrest to Inanda Dam where a stop on the edge of the escarpment prior to the descent to Kwa Ngcolozi will reward you with some of the finest views in Africa.

In the following weeks we will venture forth on a geological journey, beginning on the edge of the great ocean basins, then on to the fiery birth of the Drakensberg, down through the age of deserts, temperate swamps and dinosaurs, ice ages and ultimately to the ancient exposed bones of the Earth – the remnants of an ancient Himalayan-sized mountain chain which once straddled our province. Earth history is writ large in our own back yard – 300 million year old glacial pavements where the ice ground across the landscape are to be found just outside of Pietermaritzburg; glacial deposits lie dumped by retreating ice everywhere; 160 million year old lava and ash flows outcrop lie in the cuttings of Sani Pass, the body imprints of crocodile-sized amphibians lie preserved in the Karoo mudstones outside Estcourt, and Durban’s Berea is part of an ancient cordon of sand dunes which accumulated when sea levels were higher than they are now. We walk, in a sense, on hallowed ground, where the history of the Earth is recorded in the rocks beneath our feet, affecting us all in a myriad of ways. Our prosperity and survival is intimately entwined with the underlying geology – it provides us with metals and fossil fuels vital to modern life, forms the substrate on which we found our structures, and soil, the residue of the aeons, nourishes our crops.