Evidence for a Grounded Ice Sheet in the central North Sea during the early Middle Pleistocene Don Glaciation.

TY - JOUR

T1 - Evidence for a Grounded Ice Sheet in the central North Sea during the early Middle Pleistocene Don Glaciation.

AU - Bendixen, Carina

AU - Lamb, Rachel M.

AU - Huuse, Mads

AU - Boldreel, Lars Ole

AU - J.B., Jensen

AU - O.R., Clausen

PY - 2018/3/1

Y1 - 2018/3/1

N2 - Interpretation of 3D seismic data from the central North Sea yields evidence of a pre-MIS (Marine Isotope Stage) 12 grounded glaciation. The glaciotectonic complex shows buried push moraines resulting from the thrusting of multiple ice advance phases with horizontal shortening of 35 – 50%. The earliest feature observed within the complex, a hill–hole pair, represents the initial glaciation of the area. This is overlain and deformed by multiple thrust units with numerous inferred ice-flow directions. The thrust deformation observed shares characteristics with kinematic processes, push moraines and static gravity processes, seen as gravity spreading and contraction. The glaciotectonic complex in its entirety is interpreted to correlate to a pre-Elsterian glaciation, becaue of its stratigraphic position below central North Sea tunnel valleys, estimated to be Elsterian in age (MIS 12; 450 ka). The study proposes that the thrust complex correlates to the Donian glaciation in Russia (MIS 16; 600 ka) with ice sourced from Norway. The complex therefore represents a glaciation where a significant area of the central North Sea was covered by an ice sheet, 200 kyr prior to the Elsterian. This study highlights the fragmentary record of pre-Elsterian glaciations and the importance of incorporating offshore sedimentary archives and regional frameworks when reconstructing Pleistocene climate change.

AB - Interpretation of 3D seismic data from the central North Sea yields evidence of a pre-MIS (Marine Isotope Stage) 12 grounded glaciation. The glaciotectonic complex shows buried push moraines resulting from the thrusting of multiple ice advance phases with horizontal shortening of 35 – 50%. The earliest feature observed within the complex, a hill–hole pair, represents the initial glaciation of the area. This is overlain and deformed by multiple thrust units with numerous inferred ice-flow directions. The thrust deformation observed shares characteristics with kinematic processes, push moraines and static gravity processes, seen as gravity spreading and contraction. The glaciotectonic complex in its entirety is interpreted to correlate to a pre-Elsterian glaciation, becaue of its stratigraphic position below central North Sea tunnel valleys, estimated to be Elsterian in age (MIS 12; 450 ka). The study proposes that the thrust complex correlates to the Donian glaciation in Russia (MIS 16; 600 ka) with ice sourced from Norway. The complex therefore represents a glaciation where a significant area of the central North Sea was covered by an ice sheet, 200 kyr prior to the Elsterian. This study highlights the fragmentary record of pre-Elsterian glaciations and the importance of incorporating offshore sedimentary archives and regional frameworks when reconstructing Pleistocene climate change.

U2 - 10.1144/jgs2017-073

DO - 10.1144/jgs2017-073

M3 - Journal article

SN - 0016-7649

VL - 175

SP - 291

EP - 307

JO - Journal of the Geological Society

JF - Journal of the Geological Society

ER -