Weichselian glaciation

Weichselian glaciation was the last glacial period and its associated glaciation in Northern Europe. In the Alpine region it corresponds to the Würm glaciation. It was characterized by a large ice sheet (the Fenno-Scandian ice sheet) that spread out from the Scandinavian Mountains and extended as far as the east coast of Schleswig-Holstein, the March of Brandenburg and Northwest Russia. Weichselian glaciation was the last glacial period and its associated glaciation in Northern Europe. In the Alpine region it corresponds to the Würm glaciation. It was characterized by a large ice sheet (the Fenno-Scandian ice sheet) that spread out from the Scandinavian Mountains and extended as far as the east coast of Schleswig-Holstein, the March of Brandenburg and Northwest Russia. In Northern Europe it was the youngest of the glacials of the Pleistocene ice age. The preceding warm period in this region was the Eemian interglacial. The last cold period began about 115,000 years ago and ended 11,700 years ago. Its end corresponds with the end of the Pleistocene epoch and start of the Holocene. The name Weichselian glaciation was given by German geologist Konrad Keilhack. In other regions the glaciations of the last glacial period are given other names: for example that in the Alpine region is called the Würm glaciation, in Great Britain it is the Devensian glaciation, in Ireland the Midlandian glaciation and in North America, the Wisconsin glaciation. The Fennoscandian Ice Sheet of the Weichselian glaciation most likely grew out of a mountain glaciation of small ice fields and ice caps in the Scandinavian Mountains. The initial glaciation of the Scandinavian Mountains would have been enabled by moisture coming from the Atlantic Ocean and the mountains high altitude. Perhaps the best modern analogues to this early glaciation are the ice fields of Andean Patagonia. Jan Mangerud posits that parts of the Norwegian coast were likely free from glacier ice during most of the Weichselian prior to the Last Glacial Maximum. Between 38 and 28 ka BP there was a relatively warm period in Fennoscandia called the Ålesund interstadial. The interstadial receives its name from the Ålesund municipality in Norway where its existence was first established based on the local fossil record of shells. The growth of the ice sheet to its Last Glacial Maximum extent begun after the Ålesund interstadial. The growth of the ice sheet was accompanied by an eastward migration of the ice divide from the Scandinavian Mountains eastwards into Sweden and the Baltic Sea. As the ice sheets in northern Europe grew prior to the Last Glacial Maximum the Fennoscandian Ice sheet coalesced with the ice sheet that was growing in Barents Sea 24 ka BP (kiloannus or one thousand years Before Present) and with the ice sheet of the British Islands an about thousand years later. At this point the Fennoscandian Ice Sheet formed part of a larger Eurasian ice sheet complex —a contiguous glacial ice mass which spanned an area from Ireland to Novaya Zemlya. The central parts of the Weichsel ice sheet had cold-based conditions during the times of maximum extent. This mean that in areas like north-east Sweden and northern Finland pre-existing landforms and deposits escaped glacier erosion and are particularly well preserved at present. Also during times of maximum extent the ice sheet terminated to the east in a gently uphill terrain meaning that rivers drained into the glacier front and large proglacial lakes built up.