Tuesday, 18 July 2017

Hominin Sites and Paleolakes Drilling Project...by Jonathan Dean

Jonathan Dean (now at Hull University), who worked as  Post Doctoral Research Assistant at the British Geological Survey until February, reports on the latest group meeting of the research project he is involved with while at the BGS...

The Chew Bahir project team.
The latest meeting of the Chew Bahir portion of the Hominin Sites and Paleolakes Drilling Project took place in Potsdam in June. Chew Bahir is a lake in southern Ethiopia that was 'drilled' in 2014 to retrieve cores of lake sediment. These extend from the lake bed down to 290 metres into the sediments. This sediment accumulated over the past 500,000 years ago. I presented the isotope data that we produced at the Stable Isotope Facility at the British Geological Survey. By looking at the ratio of one type of oxygen to another, and how this varies from the present day lake bed through the sediment cores at intervals down to 290 metres, we are able to reconstruct how the climate changed between wet and dry over the past half a million years.

Our colleagues on the project are from the UK, Ethiopia, Germany and the US. Some are busy working out how old each bit of the sediment core is, e.g. using radiocarbon dating at the top and dating volcanic ash layers towards the bottom. Others are looking at changes in the type of algae found down the sediment core, to look at changes in how fresh or salty the lake water was over time. Some are taking the reconstructed climate changes and relating them to changes in human history. We want to establish what the climate was like when our species, Homo sapiens, evolved and then spread out of Africa. Some people have suggested that when climate changes from more variable to more stable, that can lead to movements of populations, but we want to test that hypothesis.

 From L-R: Location of one of the more famous Potsdam conferences, where Churchill, Truman and Stalin decided how
 to divide up Germany at the end of the Second World War; the famous Bridge of Spies in Potsdam.
While in Potsdam we visited the famous Bridge of Spies (aka Glienicke Bridge) and the Potsdam Conference venue. The bridge across the Havel River in Germany connects Berlin with Potsdam. The bridge was completed in 1907, although major reconstruction was necessary after it was damaged during World War II. During the Cold War the bridge was used several times for the exchange of captured spies and thus became known as the Bridge of Spies (several films have used this location)... The Potsdam Conference was held at Cecilienhof, the home of Crown Prince Wilhelm, in Potsdam, between July and August 1945. The conference participants were the Soviet Union, the United Kingdom, and the United States (Stalin, Churchill/Attlee, Truman). The 3 powers met to decide how to administer the defeated Nazi Germany, which had agreed to unconditional surrender nine weeks earlier.

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