Abstract
The presence and dynamics of continental glaciers dominated the physical processes of erosion and deposition in the mid-latitudes during the Pleistocene. The stratigraphy of these glacigenic deposits can be synthesized into a sedimentary facies model and used as a guide to recognize ancient temperate continental glacier deposits and to predict lithofacies variation on a local scale (of a few km) in ancient glacigenic sediments.
Deposits in epicontinental areas may extend for several hundred km and be less than 0.1 km thick as the basins created by isostatic depression are temporally and spatially limited. Thicker deposits form along continental margins intercalated with glaciomarine sediments.
Deposition from temperate continental glaciers occurs near the peripheries of the glaciers (the outer 10-100 km) and predominantly during the waning phase. Each successive glacial advance tends to erode previous deposits, leaving isolated patches of the older deposits on top of striated bedrock. A generalized sediment record consists of four superimposed diachronous lithofacies assemblages which become better sorted and finer grained up-section: 1) a subglacial lithofacies consisting predominantly of unsorted coarse-grained diamictons (tills); 2) an ice-contact lithofacies consisting of chaotically mixed, unsorted and sorted, remobilized diamictons, ice-contact lacustrine and fluvial sediments; 3) a proglacial lithofacies consisting of sorted, coarse- to medium-grained fluvial-deltaic and medium- to fine- grained deltaic-lacustrine sediments; and 4) a postglacial lithofacies consisting of very well sorted, eolian dune sand, sand sheet deposits, and loess (silt).