Structural analysis of the Rubjerg Knude Glaciotectonic Complex, Vendsyssel, northern Denmark

• DOI: 10.34194/geusb.v8.5253
• Publication Date: 2020-07-31T12:59:21Z
• Authors: Stig A. Schack Pe...
• Keywords: Thrust fault

Pedersen, S.A.S. 2005: Structural analysis of the Rubjerg Knude Glaciotectonic Complex, Vendsyssel, northern Denmark. Geological Survey Denmark and Greenland Bulletin 8, 192 pp.
 The Complex is a thin-skinned thrust-fault complex that was formed during advance Scandinavian Ice Sheet (30 000 – 26 B.P.); it well exposed in 6 km long coastal profile bordering North Sea glaciotectonic deformation revealed by this cliff section has been subjected to detailed structural based on photogrammetric measurement construction balanced cross-section. Thirteen sections are differentiated, characterising distal proximal development complex. affected three stratigraphic units: Middle Weichselian arctic marine Stortorn Formation, mainly glaciolacustrine Lønstrup Klint Formation dominantly fluvial Formation; these formations formally defined herein, together with Skærumhede Group which includes Formations. deposited regional unconformity caps separates pre-tectonic deposits below from syntectonic above.
 In part complex, architecture characterised thin flatlying thrust sheets displaced over footwall flat foreland for distance more than 500 m. Towards dip faults increases, stretches they over-steepened an upright position. lowest décollement zone about 40 m sea level system, shows systematic step-wise change higher levels (southwards) direction. elements ramps flats related hanging-wall positions. Above upper ramp-hinges, anticlines developed; synclines typically growth-fault sedimentation piggyback basins, represented Formation. Blocks slump-sheets constituting parts were derived tips up-thrusted slumped into basins. Mud diapirs prominent element resulting mud mobilisation at ramps.
 Shortening calculated as 50%. Only 11% initial units faulting lost due erosion. caused gravity spreading advancing ice sheet. Overpressured mud-fluid played important role stress transmission. average velocity displacement estimated 2 per year, led compression 12 stretch flat-lying sediments, c. thickness, length. truncated unconformity, when sheet finally overrode When melted away, hilland- hole pair formed, meltwater new ice-advance (NE-Ice) filled depression. NE-Ice overran its main stationary line situated Sea. turn away (c. 19 15 B.P.), glacial landscape draped Vendsyssel (new formation herein).