Are all glacial diamictites glacial? Implications for palaeoclimatology

Abstract

Interpretations of the origins of pre-Pleistocene diamictites are in a state of flux, changing from glacial processes to sediment gravity flows (SGFs). Working methods for the study of such deposits need to be multi-proxy and process-sedimentological and not start with presumptions based on former models or interpretations. For instance, the detailed documentation of pavements, dropstones and erratics indicate that a shift from glaciogenic interpretations to SGFs for many pre-Pleistocene diamictites is needed. In another example, surface microtextures (SM) formed by glaciers display a combination of large-scale fractures and (irregular) abrasion, in contrast to non-glacial environments, and may therefore be used as a quick diagnostic working tool.