Chapter 28 - The EISC evolution prior to the Last Glacial Maximum

Abstract

The European Ice Sheet Complex (EISC) has developed throughout the Plio-Pleistocene, undergoing cycles of ice sheet growth and retreat, and evolving in its size and configuration from several small, discrete ice sheets centred over high elevation terrain to large, coalescent ice sheet complexes independent of the underlying topography. These different ice sheet configurations may be expected to lead to a different glaciology, relationship with climate, trajectory of ice sheet growth and retreat both within and between glacial cycles and, ultimately, different glacial landscapes. Here, we provide a summary of EISC development, and the geological evidence for it, over the Plio-Pleistocene, focusing on commonalities and contrasts at ice sheet scale. Over the last 1Myr, large ice sheet complexes show two “types”: those with extensive eastern margins and thick ice cover over the Kara Sea, and those more restricted to NW Europe. We consider the implications of first-order ice sheet properties for ice–climate interactions, and of contrasting terminal settings, whether land, lake, or marine. We introduce the landscapes that yield evidence for pre-Last Glacial Maximum (LGM) ice sheets, which are largely restricted to ice-marginal zones where sediment accumulation is favoured, and parts of the interior domain where burial or cold-based ice has preserved older landscapes. A persistent challenge in reconstructing pre-LGM glaciation is the highly fragmentary nature of evidence, in both space and time, coupled to the difficulties of deriving precise age-constraint beyond the radiocarbon era. Growing understanding from more recent and well-documented time periods (e.g., LGM) that the EISC behaved in a highly dynamic manner and that geological records may be time-transgressive demand that we apply the same perspective in evaluation and interpretation of older records of EISC evolution.