Gorgon: Paleontology, Obsession, and the Greatest Catastrophe in Earth's Historyby Peter Ward
The gorgons ruled the world of animals long before there was any age of dinosaurs. They were the T. Rex of their day until an environmental cataclysm 250 million years ago annihilated them-along with 90 percent of all plant and animal species on the planet-in an event so terrible even the extinction of the dinosaurs pales in comparison. For more than a decade, Peter Ward and his colleagues have been searching in South Africa's Karoo Desert for clues to this world: What were these animals like? How did they live and, more important, how did they die?
In Gorgon, Ward examines the strange fate of this little known prehistoric animal and its contemporaries, the ancestors of the turtle, the crocodile, the lizard, and eventually dinosaurs. He offers provocative theories on these mass extinctions and confronts the startling implications they hold for us. Are we vulnerable to a similar catastrophe? Are we nearing the end of human domination in the earth's cycle of destruction and rebirth? Gorgon is also a thrilling travelogue of Ward's long, remarkable journey of discovery and a real-life adventure deep into Earth's history.
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The farmhouse has thick white stone walls, faded green trim, and an old metal roof now partially unfastened and moaning in each gust of dry African wind. It is Dutch Colonial in style, with a large living room and blackened fireplace, yellow wood floors, and high ceilings. There is no central heating or indoor plumbing. Wildlife of moderate diversity now resides in the upper story, most of it winged but with the odd resident quadruped in there as well, judging from the scurrying sounds and rodent droppings scattered about. Layered, dusty spiderwebs are the final touch of decoration, creating a tent city that gently pulses from the breezes entering the house through the many broken windows. The front of the house is graced by a handsome stone lintel, simply inscribed: tweefontein, april 30, 1863. A wide front porch beneath this dedication is lined with inset flagstones, many scored with graffiti. These now-ancient inscriptions are in square, childlike script, not at all the sort of writing polluting a modern building. Beautifully carved initials: p.f., 22 nov. 1897. On another, p.f. appears again, jan. 25, 1898. There is a c.l., m.f., c.l., 26/6/1901. And a new name, john goed, 1903. Then nothing more. The yard in front of the house is shifting dirt and dust, now home to stunted thornbushes native to the surrounding Karoo Desert. Termite mounds give relief to what was once a front lawn. Dead trees surround the house, obviously planted long ago for shade, but now casting the anorexic shadows of skeletons. Other trees farther from the house have fallen and are being reduced to dirt by the African decomposers.
To the north of the house, a barn hasalso fallen inward, and beyond that an obviously older building has decayed into ruin as well, this one made of individual stones, carefully and methodically fashioned together to form what once must have been perfectly squared cobble walls, a legacy of craftsmen with time on their hands. A stone fence of the same exquisite craftsmanship runs parallel to the older building and then disappears into a pile of rubble.
The front of the house looks west, into the sunsets, while the back is overlooked by the giant stone rampart known as Lootsberg Pass, a wall of rock that rises a thousand feet above the farm. A hard walk of ten minutes from the back of the farm takes one onto the slope that rises up onto the beginning of this wall of high sedimentary rock and capping volcanic layers. At the start of this slope, between the house and the long mountain range behind, is one final testament to a former human existence here: the family graveyard. The graveyard is perhaps twenty-five feet on a side, and to my eye it looks as if it were constructed for a Hollywood haunted-house B movie, except that this is the real thing. The graves are enclosed by a low stone wall topped by Victorian black grillework of densely packed and upthrusting iron points. Desiccated weeds now fill the walled graveyard, partially obscuring three large marble headstones. Legions of ants march between the headstones in military formation, skirting the brown wrack of dead bracken on their mindless journey through this Boer cemetery. The sun shines brightly on the dead this day, as it does on most days in the Karoo; a squadron of flies patrols its perimeter. Wind blows on the weeds among the headstones, and an African equivalent of a tumbleweed rolls up to the wall surrounding the graves, becoming suspended there. Sheep dung lies everywhere around, the universal currency of the Karoo.
The largest headstone is inscribed with two names: Anna Catherine Jacobus Fouche, born 1831, died 1892, and her husband, Francouis Petrus Fouche, born 1825, died 1894. The headstone is still pristine white save for ancient fingers of brown lichen, the marble imported-surely not of African origin-and beautifully carved. A second headstone, smaller but of the same marble, lies several feet to the side of the first. Carel Hercules Fouche, born 1856, died 1898. The third headstone, the same size as the second and the same quality as both, proclaims the resting place of Jacobus Albertus Fouche, born 1859, died 1900. And next to these three graves, all in a row, lies a fourth. An extended pile of stones shows another burial, but there is no headstone, no indication of who-or what- lies here. A family servant? A favorite dog? Or does this grave hold another Fouche whose headstone has been stolen or who did not merit one in punishment for sins long forgotten?
There is plenty of space for more bodies here. Whoever designed this graveyard had a bigger or longer lasting family in mind, and, based on the scratching on the farmhouse stones, it seems that at least some Fouches survived the rather surprising deaths of the rest of the Fouche family, for the dates of death on the headstones suggests a rather sudden end for four members of this family. How often does a family, or perhaps most of one, die out in such a short interval of time? Anna Catherine was the first to go, in 1892, at age sixty-one; her husband, then aged sixty-nine, followed two years later-a pattern often seen among grieving spouses. But the two sons, Carel and Jacobus, lasted not much longer: Carel died five years after his father, at the age of forty-two, and his younger brother, Jacobus, died in 1900 at the young age of forty-one. In eight years they were all gone. The headstones give no clue to the cause of this family's demise. Four members of a family so quickly changed from living to dead. Why? There is also no clue to be had in the nearest register of information, the Boer records in the public library in the nearby town of Graaff-Reinet. The Fouches are listed, their births and deaths recorded, but no cause of death is given. And who survived them? Who is the P.F. who scratched his name in the stone front of the house after Jacobus Fouche died? This family died out, or nearly did so, a century ago. All record of how this tragedy occurred is now lost; we have but the bodies and the birth and death dates.
The irony is sublime. Quite unknowingly, the Fouches placed their cemetery on a far older graveyard, a cemetery planted 250 million years ago whose headstone is the high rampart of rock we now call Lootsberg Pass, a sandstone and shale monument soaring up over the gothic iron grillework and marble of the Fouches' last resting place. This older fossil grave site marks the death of as many as 90 percent of all species that lived in the world at that time. But what hope is there to understand a quarter-billion-year-old tragedy, when a century-old series of deaths becomes so quickly opaque to our comprehension? At the same time, how can we not try to understand death, both recent and remote? Especially if those deaths could hold clues to the future as well as the past?
This book is about two things. The first is the search for the cause of the long-ago mass extinction so clearly marked in Africa and elsewhere around the globe, a calamity devastating enough to bring life on the earth into its most severe near-death experience. If we can find the cause, then perhaps we can predict whether such a calamitous event might be in our future as well as our planet's past. To that end I will tell a history of how research about this question unfolded in Africa. The second topic of the pages to come, however, is along a quite different tangent: why scientists would so doggedly, and at the cost of such hardship, devote their lives to pursuing this ancient killer. The popular view is that paleontology is a romantic profession. While that may be, after years of work in the heat and cold of a high desert, romance wears thin. And yet, as we shall see, the scientists portrayed in this saga slogged on and on, year after year, for little pay and even less glory. But first the extinction.
Long ago, at the beginning of Paleozoic time (some 540 million years ago), life flourished in the seas, but only bacteria and perhaps some low fungi and moss lived on land. This state of affairs did not last, and by 300 million years ago, a flourishing diversity of creatures, including a rich suite of vertebrates, inhabited the continents. By 260 million years ago land animals were as common as dinosaurs and mammals would ever be. Some would have seemed familiar enough: smaller lizards and salamander-like amphibians that were quite similar in shape (if not ancestry) to animals still living today. But the larger animals would have been totally unfamiliar, for they belonged to an assemblage of land animals completely unknown to popular culture-the mammal-like reptiles. There were many varieties of them: herbivores, scavengers, diggers, tree dwellers, and hunters.
The largest land-dwelling carnivore of 260 million years ago, the T. rex of its day, was about the size of a modern lion. But other than having a similarity in size, these ancient carnivores were surely most unlionlike in most other traits. They would have had huge heads with very large, saberlike teeth, large lizard eyes, no visible ears, and perhaps a mixture of reptilian scales and tufts of mammalian hair. Their tails would have been relatively long and reptilian, and they would have moved about on rather stumpy legs with broad, flat feet bearing hideously large claws, not retractable like those of cats, but more like those of a wolf. They must have loped after prey in a relentless fashion, legs splayed out slightly to the side, outsize, fanged heads held high. They are monsters from the dark recesses of our imagination; they are the stuff of nightmares, half dragon, half lion, cunning land sharks adapted for eating and killing. They fed on every type of larger animal then existing, some of which were the direct ancestors of all mammals living today (including humanity). They are called Gorgons.
The Gorgons ruled a world of animals that were but one short evolutionary step away from being mammals and that evolved into true mammals long before there was any Age of Dinosaurs. The Age of Mammals was set to begin some 250 million years ago but was summarily ended, or at least vastly delayed.
The very destructiveness of this mass-extinction event has led to new theories about the importance of catastrophe in determining the nature of the makeup of life on earth. To many scientists it suggests that we live in a very troubled and dangerous world, one molded and sculpted by a succession of calamities, and that these catastrophes, called mass extinctions, are the largest-scale evolutionary events affecting the biology of our planet.
There can be no doubt that mass-extinction events-there have been five, in the last 500 million years, that killed off more than half of species on earth-have led to wholesale biological changes. After all, the most famous of the mass extinctions, which killed off all dinosaurs 65 million years ago, was immediately followed by an entirely new mix of species that we call the Age of Mammals. Yet there might be an even more profound implication. Paradoxically, the mass extinctions might be of great importance in understanding the nature of the cosmos-events that might tell us something about the frequency of life in the galaxy and where to look for it. That, too, is part of the story to come.
And finally the why: Why dedicate a career and life to such a pursuit? That story is more complex, harder told, but perhaps the more interesting of the two intertwined tales I have tried to write in this book. You be the judge.
The ends of long love affairs are never painless.
For nearly a decade, I had been hopelessly, shamelessly in love with the adventure of solving a wonderful scientific mystery: what killed the dinosaurs and their ilk, 65 million years ago, in what had been named the Cretaceous-Tertiary, or K/T mass extinction. Since 1980 my world-the world of geologists, astronomers, paleontologists, geochemists, in sum, those of us interested in earth history-had been involved in the affair of our lives: the mystery behind the death of the aforesaid dinosaurs. It was a consuming affair, all-important, satisfying, demanding, engaging, frustrating, emotional, crazed. It took us to faraway places, prompted us to spend fortunes and youth, to give allegiance, to become involved in public debate and controversy and censure and comradeship on epic scales (or as epic as things get for a scientist anyway). It involved the mobilization of an army of scientists, of gatherings large and small for the dissemination of knowledge. There were riches to be gained in prestige and sometimes money, the not inconsiderable stakes of careers raised up or torn down among the various emotions of anger, nobility, jealousy, altruism, and unrequited passion by all involved. But, most important, the affair lent a wonderful scratch to that constant itch of curiosity that drives science and its motley crew of practitioners. What killed the dinosaur and so much else? Was it slow climate change, or pulsing volcanoes, or even competition from egg-eating mammals as scientists had thought ever since the first dinosaurs were discovered now nearly two centuries ago? Or was it something much more dramatic- like a really big rock falling from space? It was this latter assertion, arriving as a clarion call to action in 1980 with the now famous publication by the Alvarez group from Berkeley, that galvanized a scientific community into action. Those of us called fanned out, did our work, and within a decade ultimately proved that a ten-kilometer asteroid crashing into the earth caused an enormous and catastrophic mass extinction.
By the fall of 1991, after more than a decade of research and discovery, the affair was over. The controversy ended. Data and falsification laid bare the lie of a long, slow event caused by gradual climate change or egg-eating mammals or whatever. But resolution took away our lovely mystery. Many of us were left heartbroken at the loss.
My own work, concentrating on the fortunes of larger marine fossils that I had been collecting for ten years from the outrageously beautiful sea-cliff exposures in southern France and the Basque region of Spain, had reached an ending point at that time as well. Each year beginning in 1982, I had prospected among these most breathtaking coastal exposures of sedimentary rocks and combed the seaside strata for fossils of the long-ago Cretaceous Period. Slowly a list of species for these cliffs was erected, the cliffs and their sedimentary strata measured and cataloged, various sections correlated so that an intricate web of timelines stretched across a hundred miles of the Basque coastline. Each year I knew a bit more, and the picture of the extinction's starkness and speed became clearer. Scientific papers followed, and then a large monograph, a labor of love, publicly invisible but the stuff of progress in science, carried me as far east as Pamplona. The days were long but, in a not-so-strange way, anticlimactic. There was no more great mystery to be ferreted out of these rocks. The Cretaceous/Tertiary boundary sites in Pamplona were twins of those I had been working on since the early 1980s; the fossils told the same tale: a sudden and vicious extinction wiping out most of the marine species and all of the marine ecosystems. Like the sites I had studied near the Basque towns of Hendaye, Bidart, Sopelana, and Zumaya, the story never varied; there was little that could be added. As at the end of most major battles, now there was only mop-up work-small projects, things that were interesting but not world changing-and that was the problem, for the prior decade of work had been so exhilarating and addictive. By 1991 only a handful of doubters was left; the vast majority of those who had studied these rocky piles of strata of the latest Cretaceous age had no doubt that a great asteroid had hit the earth and that the end result of that collision had been death-death to the dinosaurs and plants on land, death to the ammonites and many other invertebrates in the sea, death in a hurry. The discoveries, the conferences, the pollination, the battles in public and print-none of us involved in the K/T-extinction controversy will ever forget it, and none of us will ever stop missing those heady days.
For me, there was one last day of work. My gear was packed, and I took a flight to London in order to wait for a visa from the South African embassy. I had to swear to them repeatedly that I was not a journalist. These were the last days of apartheid, and the great struggle that eventually toppled the long-oppressive white regime was nearing its culmination. The South Africans had no welcome mat out for journalists.
Thus, on a cool, late-fall night at Heathrow Airport in London, I checked my gear, boarded the South African Airlines jet, and headed to the other end of the world.
We cramped passengers flew all night, and early morning showed a dry countryside below. I was tired but ecstatic and excited: I had never been to Africa before. One door had closed, and another strange new door was opening. Customs was long and brutal, the agents all white and suspicious, searching, cold-eyed. The police presence was military and armed that way.
My South African colleague duly picked me up at the airport, took me to his house for a cup of tea, and then dropped me off at my hotel. It was, unhappily, a Holiday Inn. I could not stay inside this too-familiar vestige of the American life I had left, so I walked into the center of town and, in so doing, walked into Africa.
Tropical plants of deepest green, filled with strange squawking birds, lined the streets. I made my way into a central square where a huge daily bazaar was in full swing. There was a rhythm and a tempo to the life on the street that were distinctly new, and I was soon overwhelmed by the huge African marketplace economy bustling amid the grayer, drearier business buildings of downtown Cape Town. Music boomed, people bartered and thronged, there was bustle and motion everywhere-a visceral joy in living. And looming over all was Table Mountain, impossibly flat on top, a giant pile of strata towering above the city. It was mesmerizing. Cape Town, the self-proclaimed Mother City.
From the St. George's Mall marketplace, I made my way through busy streets into the Company Gardens, a more tranquil stretch of greenery, caged birds, fountains, and reflecting pools wedged between municipal museums. This huge garden gave way to my new scientific home, the South African Museum, which rose in splendor from the foliage, its turrets pointing squarely at Table Mountain. It was a Sunday afternoon, and Cape Town was crowded with kids and adults strolling through the gardens or visiting the many museums. A sharp, clear day, as so many in Cape Town are, the sky deepest blue and the wind blowing hard, sweeping away the smoke of the leechlike squatters' camps grasping the edges of the city. Table Mountain hung suspended over the museum, looking perhaps like Jupiter does from its nearby moons; even when it's not in direct sight, one knows that it looms there.
The museum was nineteenth-century ornate, a beautiful edifice and gift to the country. Sadly it was also nineteenth century in the ways of its exhibits. Long display cases filled with things old and older, great halls cluttered with aboriginal artifacts, and dioramas exhibiting Bushmen in their so-called native habitat in a fashion similar to those exhibiting the local animals in their native habitat. Nowhere, however, was there a diorama showing white people in their native habitat-or maybe that was the joke, as we white people walked through the museum staring at these representations of the "natives." Finally passing out of this sad tribute to racism, I entered the wings of paleontology, and here my pulse quickened.
Like all such exhibits, this one began with a treatise about time-geological time, that is. No other field of science has found it necessary to codify the timescale applicable to, and usually known only to, geologists. There is no formalized biological time- scale or chemical timescale, although, of course, all processes described by these two great fields have temporal components. All other fields of study simply use the intervals of time known to us all: seconds, minutes, hours, days, and so on. Geologists, on the other hand, talk about periods and epochs, eras and zones, stages and series, the arcane subdivisions of what is known as the geological timescale. All are defined by death. The bigger the division, the greater the body count. For geologists, death becomes the ticking of the geological clock.
The divisions of time used in geology come from a study of the fossil record. Major time units are recognized and defined by mass-extinction events, sudden global catastrophes causing major biotic turnovers and extinctions. Two of these were especially dramatic. At the top of strata named the 250-million-year-old Permian System-and at the top of a much younger, 65-million-year-old Cretaceous System-the vast majority of animal and plant fossils were replaced by radically different assemblages of fossils. Nowhere else in time were such abrupt and all-encompassing changes in the faunas and floras to be found. These two wholesale turnovers in the makeup of animal life on earth were of such magnitude that they were used to subdivide the geological time- scale into three large- scale blocks of time: the Paleozoic Era, or "time of old life" (extending from the first appearance of skeletonized life 530 million years ago until it was ended by the gigantic extinction of 250 million years ago); the Mesozoic Era, or "time of middle life" (beginning immediately following the great Paleozoic extinction and ending 65 million years ago); and the Cenozoic Era, or "time of new life" (extending from the last great mass extinction to the present day).
The two greatest of the mass extinctions also received attention in this musty exhibit. I was particularly interested in the explanation for the first of these two, the Permian extinction. I was not surprised to see the same cant that I had learned as an undergraduate: By the end of the Paleozoic Era, some 250 million years ago, there was but a single "supercontinent," composed of a united North America, Europe, Asia, and Africa. Two effects of this gigantic, tectonic embrace supposedly produced the extinction. First: The earth's climate changed. Because of its immense size, huge areas of this supercontinent could no longer be cooled or warmed by steadying maritime influence, and the interiors of this gigantic continent thus grew hotter in summer and colder in winter. Second, when the contents coalesced, the level of the oceans fell dramatically, causing the wide interior seas found on virtually every continent at that time to disappear. It was within these shallow seas that most Paleozoic marine life had lived. The two processes were linked. As the climate grew more arid, the shallow seas evaporated all the faster, and with their loss the climate worsened, for these great inland bodies of water must have had an ameliorating influence on the climate. The earth's species gradually succumbed to the killing climate, slowly falling away like browning leaves, a few to be immortalized in rock, the rest to pass from all memory. By the end of 10 million years, only a tiny percentage of Paleozoic species was left, land and sea creatures existing in the few temperate refuges where great equatorial heat balanced frigid polar cold. A 10-million-year extinction!
I then moved on to the explanation for the 65-million-year-old extinction of the dinosaurs. Here, too, there was an explanation based on slow climate change and a story purporting that, like the animals killed off in the older of these two mass extinctions, the dinosaurs and ammonites also had died out gradually over millions of years. But at this time in 1991, we knew that this latter explanation was wrong: The dinosaurs might have died out in as little as a few weeks following the asteroid strike, not millions of years, perhaps not even tens of years. And if one of these stories was demonstrably wrong, why not both?
I moved on to the fossils themselves, those found in the nearby Karoo Desert in rocks from the end of the Paleozoic Era: the victims of the first of the two great mass extinctions. In poor light, amid dusty and yellowing backgrounds, I again found dioramas, those favorite devices of the old days of museology. But within these were creatures completely unfamiliar to me. Nothing in popular culture-or even in my long paleontological training-had ever led me to such images: giant hulking animals with ridiculous-looking mouths and the most ungainly carriage, huge front legs and short hind legs, behemoths eight feet tall and black in color. Monstrosities.
I looked at the fading script below: moschops. a mammal-like reptile from the ancient karoo. Near it were other monsters, some carnivorous, others herbivorous, all arranged chronologically so that the visitor could see how they changed through time. It was clear that these early land-living reptiles had indeed rapidly improved from truly clumsy- looking and obviously slow-moving behemoths to more agile and clearly more active forms. As I strolled through the cases, I was a bit chagrined to realize that I knew so few of these ancient creatures, whose names were largely foreign to me. Most of the figures inspired ridicule, a combination of their design and the way in which the models had been sculpted, being rather cheesily built and painted. In one diorama a particular monstrosity struck me. Clearly a carnivore, it was an image of a demon. On the bottom was a placard proclaiming this to be a gorgonopsian. Gorgon for short. The name conjured vague images from my painfully short and shallow training in the classics. Some sort of Greek monster, a Gorgon. Three sisters, all nasty, Medusa the best known. Look at her and you turn to stone. The name sounded sinister enough, and the creature in this musty diorama did indeed evoke a shiver: I had no wish to ever confront one of these things alive. Then a different image arose in my mind: Chimera, another monster from the Greeks, with the head of a lion and tail of a serpent. That seemed as least as fitting, and a better description of how this prehistoric Gorgon may have looked when alive. A novel monster, not the familiar lion or tiger of our world, nor the equally familiar and oversold carnosaur of Jurassic Park but a new nightmare or, more correctly, a new old monster. Gorgon. nnn
Thus was passed my first afternoon in Africa. Since I had come from Europe, far to the north but neither west nor east, I was in the same time zone and felt no ill effects from jet lag. I dined, reveled in the new smells and tastes, and exulted in the clear air Cape Town is blessed with, an air cleansed by the nearby sea. It is a place that inspires a distinct delight in being alive.
The next morning I was given a small office in the museum, met with my scientific host again, and was ready to begin work. I was there to study my main research interest, fossils called ammonites, which were shelled mollusks looking much like the modern-day chambered nautilus-we think. No ammonites survived the K/T extinction, and we are left with only their fossilized remains. I was interested in comparing the ammonite fossils found in the Southern Hemisphere with those I had collected in my native North, and in this I was not disappointed. The museum's collection of ammonites was indeed magnificent. After some days studying them, however, I began itching to see them in context-to see the actual rocks from which they had come, to journey to the field and see firsthand the outcrops of Africa yielding these specimens. Of course, I also wanted to find some myself, for I am a collector deep in my heart, like all true paleontologists. So I approached my host, Herbie Klinger, and asked directions to his field area, fully expecting him to offer to take me there. It turned out that the outcrops were many hundreds of miles up the coast from Cape Town, far into the tropics of Zululand and surrounded by jungle. In a most diplomatic way (and for a variety of reasons that were unknown to me at the time) Herbie explained that he thought it unwise for me to go there. Here was a conundrum. If I wasn't able to work in the field, my options were limited. I could become a vacationer or try something else. Luckily, "something else" offered itself up relatively soon: one of the museum staff, Roger Smith by name, offered to take me to see Permian rocks in the Karoo. I knew virtually nothing about the Karoo and nothing about the Permian extinction other than its magnitude-that it was the greatest of all time. The party line in my field had been that the Permian extinction was a long-drawn- out affair, nothing at all like the very rapid Cretaceous extinction, and thus not very interesting. Nevertheless, the chance to see these famous rocks and look at a far older extinction than the one I was so actively working on was a chance not to be missed. I accepted with alacrity. And thus a change in my research direction was begun and a long partnership entered, neither of which I recognized till after.
Roger Smith is a presence. He is a head shorter than me, stocky, bearded, and weather worn. Yet he radiates an animal-like vitality, a coiled presence, affability covering careful menace. From the many photos scattered about his office, I realized that he was a distance runner of some sort. He seemed friendly enough, but he stared at me with very direct eyes, and I had the distinct impression that he was taking my measure. A very cool customer, Roger Smith. And strong-physically, mentally, emotionally. That was immediately clear. A strong man. Used to leadership. And used to living behind walls like all Brits, the heritage of privacy and stoicism.
On the appointed date, we set out, and my first surprise-shock, really-was how far away from Cape Town we had to travel to get to the Karoo. It took eight hours of fast driving to arrive at the area Roger suggested we visit, and this area was only partway into the vast expanse of dry land and semiarid desert known as the Karoo.
The drive was a journey through fantastically changing landscapes. Cape Town is located amid a rugged set of coastal mountains, and these continued inland for the first hour, a verdant green landscape of piled hills and upthrust low mountains deeply eroded. This was wine country, and for miles in either direction there were green valleys carpeted with lush vineyards. The mountains rose ever higher, and eventually we passed through a lengthy tunnel underneath the tallest peaks. When we emerged into bright sun after the long gloom, it was immediately clear that the country had changed for the drier. As we rolled on, hour after hour, the dryness increased, until Roger proclaimed what we were now in the Karoo.
The Karoo countryside is very distinctive, looking like no place I'd ever seen before. Most distinctive was the fact that all the low hills we passed had flat tops, called "kopjes." This is an odd shape for hills. Most hills are gently rounded on top, but not in the Karoo. I asked Roger about this, and he explained that the Karoo landscape came about through two very different geological phenomena that are virtually unknown elsewhere, thus giving the land its unique appearance. First, sedimentary rocks were deposited. Then these sedimentary rocks were covered and invaded by hot lava, creating a pastiche of intermixed sedimentary and volcanic rock.
Most of the rock around us was flat-lying sedimentary rock, deposited more than a quarter billion years ago. Within this rock were the fossils we had come to see. The second type of rock here is dolerite, an igneous rock that makes up the tops of higher ridges in many regions of the Karoo. Dolerite sits like a great flat sheet upon an older bed of baked rock. It is the lithic equivalent of a cancer, an obdurate invader shouldering its way into the native country rock through sheer force of heat and pressure, melting or metamorphosing the sedimentary rock that sat there first. The dolerites made their way into the other rocks here more than 180 million years ago, a time when great dinosaurs ruled the earth; when huge Brontosaurus and slavering, dagger-toothed Allosaurus roared, roamed, loped, and ruled as the top carnivore always does; and when mammals were still merely cunning nocturnal vermin living in the cracks and crannies and tenements of the Jurassic jungle, the inner-city dwellers of the forests too poorly armed and not fleet enough to make a life in the open. The mammals were the weeds of the earth when the dolerites sprang into being, vermin to be sure, but tasty, with their warm- blooded flesh covered only by hair. And while all of this living mayhem ran its course, a greater event shuddered under the feet of the Jurassic world of Africa, for it was during the Jurassic that Mother Africa, like a great cruise ship, cast off its mooring from the giant supercontinent called Gondwanaland. Gondwanaland, earlier disinct, then merged into even bigger Pangaea. The signature of this colossal and messy divorce is the dolerite lining the top of so many places in the Karoo, bits of Hades rushing up to fill the cracks as the continents spread apart.
My most vivid impression from that first day in the Karoo was that it was a land of rocks, with all else an afterthought. This is not to say that there was not vegetation; there was abundant grassland and low shrubs, and even a gnarled tree on occasion. But the plants were only spacers between the rocks, which came in all sizes, from great boulders to small cobbles. Every hour we would get out to stretch our cramped muscles and take long drinks of water against the heat, and I would try to walk across this landscape. But, as I was to learn, walking across the Karoo landscape is an exercise in avoiding rocks.
For the next several days, we looked at outcrops as geologists are wont to do. I was particularly interested in seeing the boundary between the Permian and Triassic periods-an interval defined by the most catastrophic of all mass extinctions, the Permian extinction event of 250 million years ago. I was surprised to learn that no one could really put a hand out to any given outcrop and say, "Here it is." At the K/T boundary sites, there was no ambiguity-the position of the boundary clay was obviously present and eminently visible. Here in South Africa, in rocks that had been deposited by rivers and swamps, there was no such boundary. So I asked about the fossil record here in the Karoo. Another shock. Roger told me that no one had ever collected fossils from measured sections here. In other words, although thousands of fossils had been collected from Karoo rocks, and certainly hundreds that would not only be highly relevant in trying to ascertain not only where the extinction level in these rocks lay but also potentially yield important information about the why of the extinction among vertebrates, no one had yet conducted research of sufficient precision to attack this problem.
We had booked into a small suite of cottages in the town of Graaff-Reinet, one of the bigger towns in the Karoo. It was charming-Old Dutch architecture everywhere-and over a fine dinner, we planned the next day's activity. Roger suggested that we climb one of the odd conical hills (something akin to a mesa) that make up the Karoo landscape. On this climb we might pass through the Permian/Triassic-extinction boundary.
The next day we made the climb-and never saw a single fossil. Roger assured me that they were indeed there, but I didn't see a scrap of bone. This was my first indication of how hard the scheme then hatching in my brain-a study of the ranges of the mammal- like reptiles across the boundary-would actually be to realize. We did see fossils at other localities, and sometimes huge numbers of bones, enough to whet the appetite of any bone hunter, but around the boundary between the Permian- and Triassic-aged rocks-known as the Permian-extinction boundary-there was nothing.
After two days of looking at various localities, we headed back to Cape Town, deep in conversation throughout the daylong drive. I had seen puzzling but enticing clues, things that made me realize that there was a better-than-even chance that the Permian extinction-at least here, among the mammal-like reptiles-was anything but the long, slow, drawn-out event that was portrayed in all the geology books of the time. Could it not have been as fast as the K/T event, perhaps even resulting from the same cause-a giant asteroid hitting the earth some 250 million years ago? I knew that, soon after the Alvarez announcement in 1980, there had been a flurry of excitement in China, caused by the reported discovery of iridium in a Permian-extinction boundary layer there-sure evidence of an asteroid impact with the earth. The Chinese came forth with this discovery in triumph. But that triumph was short lived. Retesting of these same rocks by other labs could not confirm the Chinese discovery.
Now, some ten years after that first, false announcement by the Chinese, there was still no consensus about the cause of the Permian-extinction event. But no one had ever looked at the Karoo rocks in any detail, certainly not in the way that we Cretaceous workers had studied the K/T boundaries throughout the world. No one had ever sampled the boundary for its fossils and geochemistry in such a way as to refute the possibility of an asteroid impact at the end of the Permian Period. The decade of work by so many of us on the number of K/T boundaries around the world provided a plan, a map, a working model of how to proceed here. And so, on the long drive back, I tried to instill this same sense of excitement in Roger Smith, who at that time worked on how rivers deposited strata and on how dead animals became fossils, but not on a far larger question: What caused the greatest mass extinction of all time? Perhaps the clues lay in the Karoo. Perhaps a huge scientific prize was ours for the discovering. Roger, it turned out, was a very good listener.
I came back to my desk at the museum filled with excitement. And ignorance. To do anything with the Permian extinction, I would first have to go back to school or, more appropriately, to walk the paths of those who came before, those who first brought the Age of Protomammals to life, those who named them and reconstructed them. Before I could understand how the animals and plants of the Permian died, I would have to know how they lived. I had to turn to books and weeks of study to uncover first clues to the secrets of the dry desert that had now worked itself under my skin.
Meet the Author
Peter Ward, a recognized authority on mass extinctions, is professor of geological sciences at the University of Washington in Seattle. His books include Future Evolution, The End of Evolution, and, with Donald Brownlee, Rare Earth and The Life and Death of Planet Earth.
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