I have a little link to the time before the English Channel formed 450,000 years ago. Almost every day in the last academic year, a PhD student has been working in my office. He is investigating the environment and ecology of the West Runton Freshwater Bed, a fine-grained sediment laid down by a river, between 780,000 and 600,000 years ago. The post-graduate is using pollen, fungal spores, and beetles to work out an extremely detailed reconstruction of this place and time.
What would a PhD student researching ancient sediment in Norfolk, find at Plymouth City Museum and Art Gallery? The answer lies in what he is discovering in the sediment. He is looking for tiny fragments of beetle body parts: dozens of tiny wing parts, thoraces, and heads all turn up through very careful sieving. And by using our collection of British Beetles, he is beginning to identify species and shed light on ecosystems long gone. The West Runton Freshwater Bed contains not only mini-beasts, but also giants.
I have been wanting to write a post on how the English Channel formed for quite a while, and luckily a perfect opportunity came up thanks to a recent documentary on Channel 4. Co-founder of the fantastic Trowelblazers, the wonderful Tori Herridge presented an awesome documentary about this very topic in Walking Through Time. Tori’s enthusiastic and natural presenting took us effortlessly across Norfolk and over to Kent, taking us on a journey back to when beetles scurried under the feet of the giant mammoths, and to an incredible event that separated Britain from Europe. (For tweets, and more links to information about the documentary, have a look at #WalkingThroughTime on Twitter.)
To set the scene for how the English Channel formed, we need to travel to the north coast of Norfolk, to the small green village of West Runton. Sat in an Area of Outstanding Beauty, lies a fine grained sediment formation known as the West Runton Freshwater Beds. This sediment was laid down around 780,000 years ago, when the area was a huge river estuary, with fine delta sediments building up. In these sediment are clues to the past. Tiny fragments of beetles give us temperatures and habitats, plant pollen provides us with details of the rich vegetation around, and fossils of larger animals show the ecosystem as a whole.
Norfolk was extremely different back then. There was no English Channel. Britain was joined to mainland Europe allowing animals to freely roam. Cave lions, sabretooth cats, lynx, hyenas, the extinct rhino Stephanorhinus hundsheimensis, jaguars, and giant deer all show how incredibly rich and diverse this environment was. Then in 1990, something much, much bigger was found. Just before Christmas, Margret Hems and her husband Harold, went on a spot of fossil hunting on West Runton beach. Excavations over the next few years revealed an almost complete skeleton of a Steppe Mammoth (Mammuthus trogontherii). It is the largest and most complete British Mammoth specimen, and the oldest, dating to around 600,000 years ago. (Full details on this awesome discovery are outlined by Trowelblazers).Steppe Mammoths were amazing creatures. Evolving from the Southern Mammoth somewhere around 700,000 years ago, probably in Siberia, the enormous Steppe Mammoth spread far across Europe and Asia. One population of Steppe Mammoths evolved into the more familiar Woolly Mammoth, which were smaller and better adapted to the increasingly cold environments punctuating the late Middle Pleistocene. Taller than a double decker bus, the West Runton Mammoth (previously called the West Runton Elephant) was a huge beast. The size of the tusks, along with the pelvis suggests it was a male, and the teeth indicate it was around 40 years old. The skeleton provides answers to the death of this giant. An injury on the bottom-end of the thigh bone shows that it didn’t sit in the knee socket properly, so at some point this individual dislocated his knee. It seems as though he fell, or lay down, only never to get up again.
Ancient footprints at Happisburgh shouldn’t have been a huge surprise. Just over 10 years earlier a beautiful flint hand axe was found in sediment from an ancient river bed. The flint itself can’t be dated, but the sediment it was found in can: it was dated to around 500,000 years old. This exquisite hand axe was carefully knapped by someone half a million years ago! The owner of the axe is likely to have belonged to Homo heidelbergensis which is a hominin species from this time. Fossils of H. heidelbergensis have been found in Spain and Germany, and at Boxgrove in Britain. The stunning hand axe is currently on display in the natural history gallery at Norwich Castle Museum and Art Gallery.
It is hard to imagine Norfolk full of exotic beasts joined to mainland Europe, with at least two species of humans visiting. For us today, it is hard to imagine what Britain would have been like without the English Channel: something, which is quite dearly British. However, the English Channel formed relatively recently, and it was something quite incredible. Around 450,000 years ago Britain was in the grip of possibly the coldest period in its recent history. This major glacial period, was so cold that an enormous glacier covered most of Britain, much of the North Sea, northern Germany, Denmark and Norway. This massive slab of ice was so far south in Britain, it pushed the River Thames south to it’s current position.
Just off the coast of Norfolk, was an enormous lake. Fed by meltwater from the enormous glacier, this lake grew to be twice the size of Wales. The lake was dammed by a chalk ridge, stretching from Dover all the way across to northern France. Made from billions of tiny microscopic organisms drifting to the ocean floor, chalk is a pretty weak rock. It is thought that a small earthquake weakened the chalk ridge, and the lake broke through the dam, with a flow rate 300 times that of Niagara Falls: a mega-flood. That’s a pretty powerful force. So powerful, the force of it would rip a valley out of any rock beneath it. And that is exactly what Dr Jenny Collier and researchers at Imperial College London discovered 40 meters below the waves. The force of huge amounts of water gouged out valleys on the floor of the English Channel. The mega-flood happened, and it would have been an incredible, if terrifying, sight.
Walking Through Time took us back to a time when the Steppe Mammoth plodded through Norfolk, and to the formation of the English Channel. This documentary brought some excellent science together, which may have otherwise been missed by non-specialists. New research will bring even more detail to this enigmatic time before and after the mega-flood. Today, more than ever before, science is being made more and more accessible. Allowing more and more people to walk though time.
Written by Jan Freedman (@JanFreedman)
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