New age constraints for the Saalian glaciation in northern central Europe: Implications for the extent of ice sheets and related proglacial lake systems

Abstract

A comprehensive palaeogeographic reconstruction of ice sheets and related proglacial lake systems for the older Saalian glaciation in northern central Europe is presented, which is based on the integration of palaeo-ice flow data, till provenance, facies analysis, geomorphology and new luminescence ages of ice-marginal deposits. Three major ice advances with different ice-advance directions and source areas are indicated by palaeo-ice flow directions and till provenance. The first ice advance was characterised by a southwards directed ice flow and a dominance of clasts derived from southern Sweden. The second ice advance was initially characterised by an ice flow towards the southwest. Clasts are mainly derived from southern and central Sweden. The latest stage in the study area (third ice advance) was characterised by ice streaming (Hondsrug ice stream) in the west and a re-advance in the east. Clasts of this stage are mainly derived from eastern Fennoscandia. Numerical ages for the first ice advance are sparse, but may indicate a correlation with MIS 8 or early MIS 6. New pIRIR290 luminescence ages of ice-marginal deposits attributed to the second ice advance range from 175 ± 10 to 156 ± 24 ka and correlate with MIS 6. The ice sheets repeatedly blocked the main river-drainage pathways and led to the formation of extensive ice-dammed lakes. The formation of proglacial lakes was mainly controlled by ice-damming of river valleys and major bedrock spillways; therefore the lake levels and extends were very similar throughout the repeated ice advances. During deglaciation the lakes commonly increased in size and eventually drained successively towards the west and northwest into the Lower Rhine Embayment and the North Sea. Catastrophic lake-drainage events occurred when large overspill channels were suddenly opened. Ice-streaming at the end of the older Saalian glaciation was probably triggered by major lake-drainage events

Ice‐marginal forced regressive deltas in glacial lake basins: geomorphology, facies variability and large‐scale depositional architecture

“…These data provide a bridge between outcrop-facies architecture and the larger-scale Winsemann et al (2007Winsemann et al ( , 2009Winsemann et al ( , 2011 and Lang et al (2018). These data provide a bridge between outcrop-facies architecture and the larger-scale Winsemann et al (2007Winsemann et al ( , 2009Winsemann et al ( , 2011 and Lang et al (2018).…”

“…Luminescence data of ice-marginal deposits (Roskosch et al 2015;Lang et al 2018) point to several ice advances into this area during the Middle Pleistocene (Marine Isotope Stages MIS 12 to 6). were reached during the Saalian glaciation, with lakelevel rises of up to 150 m within a few hundreds to thousand years Lang et al 2018). These proglacial lakes were characterized by overall water rises during ice advances, when lake-overspill channels were successively closed.…”

“…The blocking of river valleys by the Middle Pleistocene Elsterian and Saalian ice sheets led to the repetitive formation of proglacial lakes (Eissmann 2002;Winsemann et al 2007Winsemann et al , 2009Roskosch et al 2015;Lang et al 2018). During deglaciation, the lakes catastrophically drained due to the renewed opening of lake outlets, which caused rapid, high-magnitude lake-level falls in the range of 20-80 m within perhaps a few weeks (Meinsen et al 2011;Winsemann et al 2011Winsemann et al , 2016Lang et al 2018). Maximum lake levels of~200 m a.s.l.…”

“…These deltas commonly evolve from ice-contact systems to glacifluvial deltas during icemargin stillstand and retreat (Lønne 1995;Dietrich et al 2017) and delta foreset-topset contacts can be used as water-level indicators if shoreline features are poorly developed or became eroded by later peri-and paraglacial processes (Winsemann et al 2009Perkins & Brennand 2015;Lang et al 2018). These deltas commonly evolve from ice-contact systems to glacifluvial deltas during icemargin stillstand and retreat (Lønne 1995;Dietrich et al 2017) and delta foreset-topset contacts can be used as water-level indicators if shoreline features are poorly developed or became eroded by later peri-and paraglacial processes (Winsemann et al 2009Perkins & Brennand 2015;Lang et al 2018).…”

The Middle Pleistocene glaciolacustrine environment of an ice‐dammed mountain valley, Sudeten Mountains, Poland

“…Glaciolacustrine environments associated with Saalian glaciation in mountains are of particular interest as they may have formed in distinctive morphological situations (Lang et al . ; Winsemann et al . ).…”