Plate tectonics, the Deccan Traps and an asteroid slamming into the earth is a dramatic way to start the evolution of Homo sapiens, but without these events the path of evolution would have been vastly different.
The largest natural explosion in modern times was the the explosion of the volcano Krakatoa in 1883. This explosion was equal to 13,000 times the nuclear yield of the “Little Boy” bomb that devastated Hiroshima. Tsunamis from the eruption of Krakatoa surged all around the Pacific Ocean, even rounding South Africa into the Atlantic Ocean with waves lapping on northern European and British shores. Just to remind us that magma chambers are still bubbling under Indonesia the remains of the original island of Krakatoa , Anak Krakatau, “Baby of Krakatoa” exploded in 2018 creating another tsunami spreading death and destruction.
In the 16th century BC there was a volcanic explosion which dwarfed the eruption at Krakatoa, the eruption of the volcano on the island of Santorini (Thera) in the Mediterranean. Crete and the Minoan civilisation was the most advanced culture in the Mediterranean from about 2700 BC to 1450 BC and preceded the Mycenaean civilisation of ancient Greece. Though based on Crete the Minoans had colonies around the Mediterranean, the Near East and Egypt, and with their position at the centre of the then worlds trade routes. Crete and the Minoans became prosperous with a prosperity that collapsed in the 16th century BC, to linger on for another fifty years before the peaceful and efficient Minoan bureaucracy disintegrated as the warring city-state of ancient Greece dominated the Mediterranean, with even the Minoan language disappearing. The Santorini eruption was five times more powerful than Krakatoa, and being confined to the Mediterranean the devastation was catastrophic with environmental effects being felt over the planet and as far away as China and the Americas, and led to several years of cold, wet summers in the region, ruining harvests.
An enormous eruption of one of Iceland’s volcanos in 536 AD caused the earth to again plunge into darkness for 18 months as the volcano belched a thick cloud of smoke and ash across the northern hemisphere, blocking the Sun, causing temperatures to drop to 2.00 degrees centigrade with the following decade being the coldest for 2300 years. The collapse of agriculture resulted in famine throughout Europe with a starving population being further hit with Bubonic plague in 541 AD bringing Europe to a standstill until 700Ad. With the knowledge of the devastation caused by recorded volcanic explosions it is difficult to comprehend effect of the Chicxulub asteroid, an explosion that has been estimated as science have been a billion times more powerful than the atomic bomb that was dropped on Hiroshima.
There is some debate as to whether the Deccan Traps or the Chicxulub asteroid were the primary cause the period of extinctions at the boundary between Cretaceous and Tertiary time periods known as the KT Boundary. Professor Mark Richards and a team of geophysicists from U C Berkeley consider that “The uncomfortably close coincidence between the Deccan Traps and the asteroid impact… If you try to explain why the largest impact we know of in the last billion years happened within the same geological period as these massive lava flows at Deccan … the chances of that occurring at random are minuscule,” said team leader Mark Richards, a professor of Earth and Planetary Science. “It’s not a very credible coincidence.” Richards and his colleagues marshal evidence for their theory that the impact reignited the Deccan flood lavas in a paper published in The Geological Society of America Bulletin.
66 million years ago, the reign of Dinosaurs, who had been calmly munching on plants and each other during the Jurassic and Cretaceous periods for 160 million years came to a sudden end. This event became known as the K-T mass extinction because it occurred at the boundary between the Cretaceous (K) and Tertiary (T) time periods. A massive asteroid with a diameter of over 10 kilometres (6 miles) crashed into the earth at what is now Chicxulub, Mexico, at a speed of 44,600 miles per hour creating a crater of 180 Km, (112 Miles) big enough to swallow the Isle of Wight and with the explosive power equal to 7 billion Hiroshima atom bombs. Luis Alvarez, the Nobel-prizewinning physicist, who in 1980 suggested that a huge worldwide spike in iridium, a metallic chemical element contained in meteorites, dated from 66 million years ago. A crater the size of large meteorite impact was discovered in the sea off Chicxulub by Glen Penfield, a geophysicist looking for petroleum in the Yucatan during the late 1970’s but it was not until 2016 that the size of the crater as being confirmed as that of a comet. Geologists were not impressed with Alvarez’s claims, what was a physicist doing muscling in on their territory. Accusations of incompetence, deceit and dirty tricks flew both ways. In a famous observation Alvarez declared “I don’t like to say bad things about palaeontologists, but they’re really not very good scientists…they’re more like stamp collectors”
The effects of the Chicxulub impact would have been catastrophic to the planet on its own without the vibrations echoing around the world and kicking off eruptions in the Deccan Traps in India. The result would have been an estimated 325 gigatons of sulphur and 425 gigaton of carbon dioxide from Chixulub and the sulphurous gases and ashes from the Deccan Traps which would have covered the earth not only with gasses but a layer of soot which combined with more carbon dioxide and other noxious climate-modifying gasses would have plunged the earth into a dark nuclear winter lasting a number of years.
During the nuclear winter darkness, photosynthesis on land and sea ground to a halt, killing 75% of all plant life for decades, causing the extinction of the plant eating dinosaurs, followed by the carnivore dinosaurs which preyed on them. The only survivors would have been worms and insects who thrived on decomposing matter and small creatures scurrying around the debris who fed on them, as well as smaller dinosaurs, who are still swooping and flapping around us today as they evolved into birds and small rodent size creatures which evolved into every mammal that exists today. The only larger animals which seem to have survived appears to be crocodiles and members of the Crocodylidae family which even today have the ability to survive in a dark and cool environment with scarce food. Even though the average African wild life television documentaries give the impression that crocodiles spend all their time munching on wildebeests and zebras who dare to cross a river, crocodiles only feed about 40 times a year and regularly go a year without feeding. The longest a crocodile in captivity has gone without food is 3 years.
The science and of the knowledge of plate tectonics is a comparatively recent science discipline. But, as far back as the 16th century observant cartographers such as the Dutch mapmaker Abraham Ortelios had noticed the similar shape between certain continents, and proposed that the Americas had been “Torn away from Europe and Africa by earthquakes and floods. In 1900 the American geologist Frank Taylor suggested that continents moved around, and as they collided would have formed the worlds mountain chains.
In 1912 Alfred Wegener the German geophysicist and meteorologist proposed that the continents were slowly drifting around the earth. As with Alvarez’s hypothesis on the Chicxulub impact Wegener’s views were criticised by most geologists, what could a meteorologist with no formal education in geology know about the physical structure and substance of the earth. Nonetheless Wegener’s opinions were championed by the British geologist Professor Arthur Holmes who was the first scientist to grasp the mechanical and thermal implications of mantle convection, and The American geologist Frank Taylor suggested in 1900 that continents had moved around and as they collided would have forced up the worlds mountain chains, Taylor’s theories were considered too crazy by other geologists to merit serious attention. In his book “The Earths Shifting Crust” Charles Hapgood and other geologists considered Taylor’s, Wegener’s and Holmes’s theories too crazy to merit serious attention. In the 1970’s in the geological text book “Earth” Harold Jeffreys insisted that plate tectonics was a physical impossibility, and as late as 1980 in “Basin and Range” John McPhee pointed out that even at this late date nearly 15 per cent of American geologists still did not accept that plate tectonics was possible.
Wegener had studied plant and fossil differences realised that plant and animal fossils repeatedly turned up on opposite sides of oceans, and deduced that would have been Impossible for animals and plants to get from Eurasia and Africa to America, and how coal seams with tropical plant fossils migrate from tropical climates to frozen places over 600 km north of Norway. Wegener’s theory was that there had to at one time be a single land mass which he called “Pangaea” where plants and animals mixed together before the land mass split up and floated to their present locations. Wegener published his ideas in his book “The Origins of Continents and Oceans” in 1922. Geologists were very dismissive of Wegener and pointed out that he was not a trained geologist, but merely a meteorologist who’s discipline was weather. Modern science has proved Taylor, Holmes and Wegener correct. True, there are often disagreements between geologists, as well as between geologists and palaeontologists, and both disciplines and science. Nevertheless modern science in the form of DNA and gene sequencing and radiocarbon dating have not only been a marvellous tool for geologists, but in many cases confirmed theories that geologists and palaeontologists deducted by having only knowledge and estimated timescale of strata that artefacts were found in each strata.
We now know that there have been numerous compacting and separations of tectonic plates as various land masses came together and separated to form minor supercontinents and then single massive continents, with at least 6 major supercontinents when all the continents of the world combined to form single world land masses. It is not unusual to find the same dinosaurs in Europe and North America from when these continents were once joined. When the major supercontinent Pangaea broke up to form separate land masses with the land mass Gondwanaland drifting south to form a minor supercontinent and the remaining land mass, Laurasia, drifting north, many smaller plates broke away from the continents as we know them today and drifted off to different locations far from their original tectonic plate,
Pangea started breaking up 300 million years ago, and approximately 80 million years ago, the part that had drifted south to form the minor supercontinent Gondwanaland, started to break up and parts began to drift north again. India broke away from Australia and, in geological timescale’s, was careering north and, 10 million years later, collide with Eurasia thrusting up the great mountain ranges of the Himalayas. Geological and scientific detective work discovered that the fossils in rocks in the north of Loch Ness in Scotland are not found in the rocks south of the loch, but are found in rocks in North America and Newfoundland indicating that the north of Scotland broke away from Newfoundland and drifted back across the Atlantic Ocean to join up with the British Isles. DNA analysis have confirmed that Milyeringa, blind freshwater fish living in total darkness in limestone caves in Australia are closed relatives to Typaleotris blind freshwater fish in Madagascar and India and could not have traveled across oceans. Madagascar must have been part of india and Australia. What is even more puzzling and will require a lot more detective work, is that in 2018 Jack Mulder, a geologist at Australia’s Monash University, discovered that a large crop of rocks in Tasmania were different from adjacent rocks, but had the same fossil composition as the Grand Canyon on the other side of the Pacific Ocean. How did rocks from the Grand Canyon, which is over 700 kilometres inland from the Pacific Ocean get to almost the other side of the ocean to Australasia?
Underneath India, in a massive area, known as the “Deccan Traps, was an enormous magma chamber which accompanied India and accelerated its tectonic plate’s drift north. Although some scientists believe that the Deccan Traps began erupting before the asteroid impact at Chicxulub, UC Berkeley researchers consider the impact triggered off colossal eruptions which covered an area of 1.5 million square kilometres, which is approximately half the size of modern India and lasted for 30,000 years. Part of north America was still attached to Eurasia, south America and what we now call Mexico had broken away from Africa and had not yet joined onto north America, where Mexico now exists was a shallow sea and this was where the Chicxulub asteroid struck plunging the earth into darkness and gloom for at least 10, some estimates, 100’s of years. These then were the conditions on our planet when those first little mammals were scampering around in the semi-darkness.
As warmth and sunshine started to return, and dormant plant seeds began to germinate, insect and animal life started to recover and those small rodent type mammals evolved and diversified into the over 8 million that exist today. Like the dinosaurs before the KT Boundary, some of the new mammals were plant and insect eaters and some became carnivores. To evade the carnivores some of the smaller mammals took to the trees, where they could supplement their plant diet with fruit and other smaller tree dwelling creatures who also thought they could find sanctuary in the tree tops. Some of these tree dwelling mammals evolved into the ancestors of primates about 55 million years ago, which in geological time scales is pretty soon after the K-T mass extinction.