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Early PleistoceneNo sediments of this age are known on land in Shetland but the main events can be inferred by reference to offshore sediments. The temperature curves derived from careful analysis of North Atlantic sediments indicate that the Early Pleistocene was a period of multiple warm and cold cycles with a periodicity of around 40 ka. The intensity of these cycles did not match, however, those of the Middle and Late Pleistocene. The first arrival of ice-rafted debris in North Atlantic sediments occurs as early as 2.4 Myr. Sediments in the basins around Shetland show little direct evidence of glaciation, although it is possible that small ice caps developed over parts of the islands prior to 1 Myr ago. The first evidence of Scottish ice sheets in the northern North Sea is at around 1.1 Myr and it would be surprising if Shetland had not been glaciated at around that time. |