Ice Ages in Oxfordshire
In addition to fossils dating from the icy, glacial periods of the Pleistocene, there are also a variety of interglacial fossils in the Museum's collections. By comparing interglacial fossils to glacial fossils, we can gain valuable insights into how life on Earth has responded to past periods of environmental change, and project how today's wildlife will respond to future warming caused by human-induced climate change.
Six miles west of Oxford, the village of Stanton Harcourt resides next to a fossil site rich in interglacial material from a warm spell that took place 200,000 years ago. Detailed excavations of ancient river sediments in the 1990s revealed over 1500 fossils belonging to large mammals, like elephants, mammals, bison, lions and bears. Even more exceptionally, thousands of remains of plants, insects and molluscs have been uncovered, allowing us to reconstruct this ancient environment to an unparalleled degree. There are even traces of early humans to be found at the site, with stone tools excavated from layers dating to 200,000 years ago. These tools would have been made by Homo neanderthalensis, or Neanderthals, which began to inhabit Britain as far back as 400,000 years ago.
What Oxfordshire might have looked like during interglacial periods of the Pleistocene
MAMMALS
PLANTS
INSECTS
MOLLUSCS
54 species of molluscs, including freshwater clams, mussels, limpets and snails, were found at Stanton Harcourt. These included whole layers of clam and mussel shells, sitting in 'life position', i.e. laid out as they would have been when living in the river.
Freshwater mussels excavated from Stanton Harcourt.
Photo by Kate Scott.
What Oxfordshire might have looked like during glacial periods of the Pleistocene
A number of Oxfordshire's fossil sites date to the colder, glacial periods of the Pleistocene. During these freezing spells, much of Britain's landmass would have been inhospitable to wildlife, covered in kilometre-thick ice sheets.
The most recent of the glacial periods in Britain is known as the Devensian. During the Middle Devensian, the climate warmed slightly, allowing grasslands to spread over the UK. Despite the bitter cold, these vast, grassy plains were able to support huge herds of grazing mammals. This would have included woolly mammoths, woolly rhinos, steppe bison, horse, and reindeer, accompanied by carnivores like spotted hyaenas, wolves, lions, and brown bears. So far, we have uncovered over 1000 fossils of large mammals in Oxfordshire that date to Middle Devensian (30,000 – 60,000 years ago), a number of which have been found in gravel pits like those at Sutton Courtenay. As well as finding direct evidence of species through fossilised bones, the characteristic gnaw-marks of hyaena teeth on woolly rhino and bison bones tell us who would have been eating who! Findings of stone tools from this era prove that humans were active in the landscape too. These tools were probably made by some of the last Neanderthal populations in Europe, just before our own species, Homo sapiens, first arrived in Britain ~40,000 years ago.
Acknowledgements:
Neil Adams (content) – Hilary Ketchum (content) – Neil Owen (illustrations)
With thanks to the Street Foundation.
We acknowledge the assistance of the Curry Fund of the Geologists' Association.
