TY - JOUR

T1 - Impact of Middle Pleistocene (Saalian) glacial lake-outburst floods on the meltwater-drainage pathways in northern central Europe

T2 - Insights from 2D numerical flood simulation

AU - Lang, Jörg

AU - Alho, Petteri

AU - Kasvi, Elina

AU - Goseberg, Nils

AU - Winsemann, Jutta

N1 - Funding Information: Funding for this study was provided in the framework of the “Wege in die Forschung” program by Leibniz Universität Hannover (project title: “Mittelpleistozäne Megafluten in Norddeutschland: Auswirkungen und Magnituden”; Grant No. II-05-2014-05 ). Additional funding was provided by the Academy of Finland Strategic Research Council project “COMBAT” (Grant No. 293389 ). R. Pioch, J. Sievers and T. Steinbrecher are thanked for GIS work. The hill-shaded relief maps were produced using Copernicus data and information funded by the European Union (EU-DEM layers) . Borehole data were generously provided by Niedersächsisches Landesamt für Bergbau, Energie und Geologie (LBEG). Fugro is acknowledged for providing GeODin, which was used for borehole-data management. Constructive reviews by J. Herget and an anonymous reviewer are highly appreciated and helped to improve our manuscript.

PY - 2019/4/1

Y1 - 2019/4/1

N2 - The terrestrial margins of the Middle Pleistocene ice sheets in northern central Europe were characterised by the formation of extensive ice-dammed lakes, which were controlled by the blockage of spillways by the ice margin. The largest ice-dammed lake had a volume of ∼224 km³ and formed in a late stage of the first Saalian ice advance (MIS 6) in central Germany. The failure of the ice dam in the bedrock-outlet channel triggered a major glacial lake-outburst flood. Flood-related erosional and depositional features include large-scale scours, trench-like channels, streamlined hills, giant bars and run-up deposits, indicating a wide spreading of the outburst flood in an early stage and the incision of trench-like valleys in a later stage. The incision of large valleys in the proximal flood pathway strongly impacted the regional drainage system by providing an efficient drainage network. The trench-like channels initiated by the lake-outburst flood became a crucial part of the ice-marginal drainage and subsequent fluvial system. The reconstructed outlet hydrographs imply peak discharges of 465,000–673,000 m³s −1 . The numerical simulation indicates flow depths of up to 87 m, flow velocities of up to 7 ms −1 , peaks of the bed-shear stress of 2500 Nm −2 and the inundation of large parts of northwestern Germany and the northern Netherlands. The numerical simulation of the outburst flood was conducted on both the modern digital elevation model and on palaeotopographic models, representing the palaeotopography prior to the outburst flood and during maximum flood-related incision, respectively. Distally, the outburst flood probably followed an east-west trending route through northwestern Germany and the central Netherlands into the ice-dammed lake in the southern North Sea Basin. The added water volume might have led to the overspill and drainage of the proglacial lakes in the central Netherlands and the North Sea Lake in a chain reaction, eventually opening an east-west trending meltwater-drainage pathway along the southwestern margin of the decaying ice sheet.

AB - The terrestrial margins of the Middle Pleistocene ice sheets in northern central Europe were characterised by the formation of extensive ice-dammed lakes, which were controlled by the blockage of spillways by the ice margin. The largest ice-dammed lake had a volume of ∼224 km³ and formed in a late stage of the first Saalian ice advance (MIS 6) in central Germany. The failure of the ice dam in the bedrock-outlet channel triggered a major glacial lake-outburst flood. Flood-related erosional and depositional features include large-scale scours, trench-like channels, streamlined hills, giant bars and run-up deposits, indicating a wide spreading of the outburst flood in an early stage and the incision of trench-like valleys in a later stage. The incision of large valleys in the proximal flood pathway strongly impacted the regional drainage system by providing an efficient drainage network. The trench-like channels initiated by the lake-outburst flood became a crucial part of the ice-marginal drainage and subsequent fluvial system. The reconstructed outlet hydrographs imply peak discharges of 465,000–673,000 m³s −1 . The numerical simulation indicates flow depths of up to 87 m, flow velocities of up to 7 ms −1 , peaks of the bed-shear stress of 2500 Nm −2 and the inundation of large parts of northwestern Germany and the northern Netherlands. The numerical simulation of the outburst flood was conducted on both the modern digital elevation model and on palaeotopographic models, representing the palaeotopography prior to the outburst flood and during maximum flood-related incision, respectively. Distally, the outburst flood probably followed an east-west trending route through northwestern Germany and the central Netherlands into the ice-dammed lake in the southern North Sea Basin. The added water volume might have led to the overspill and drainage of the proglacial lakes in the central Netherlands and the North Sea Lake in a chain reaction, eventually opening an east-west trending meltwater-drainage pathway along the southwestern margin of the decaying ice sheet.

KW - Glacial lake-outburst flood

KW - Ice-dammed lakes

KW - Meltwater-drainage systems

KW - Middle pleistocene glaciations

KW - Numerical flood simulation

KW - Palaeotopography

UR - http://www.scopus.com/inward/record.url?scp=85062231932&partnerID=8YFLogxK

U2 - 10.1016/j.quascirev.2019.02.018

DO - 10.1016/j.quascirev.2019.02.018

M3 - Article

AN - SCOPUS:85062231932

VL - 209

SP - 82

EP - 99

JO - Quaternary Science Reviews

JF - Quaternary Science Reviews

SN - 0277-3791

ER -