An Encyclopaedia of Indian Archaeology v1.c12.s3.2

v1.c12.s3.2

During the life span of 4500 million years of the earth it has experienced several ice ages, each lasting several million years. In the intervening periods there were practically no polar ice caps. The most recent Ice Age started around 1·8 million years and still continues. During this period ice sheets over the poles and high mountains have extended and contracted in complicated patterns. Colder periods are termed ‘glacials’ and warmer ones ‘interglacials’. At the peak of the Last Glacial the ice sheets extended as far down as 40° N. in N. America and 52°30′ N. in Europe and, as a result of locking up of vast amounts of water in these ice sheets, the sea-level went down to 100 to 150 m below the present level.