Rift kinematics preserved in deep-time erosional landscape below the northern North Sea

Abstract

Our understanding of continental rifting is largely derived from the stratigraphic record. This archive is, however, incomplete as it does not capture the geomorphic and erosional record of rifting. New 3D seismic reflection data reveals a Late Permian-Early Triassic landscape incised into the pre-rift basement of the northern North Sea. This landscape, which covers at least 542 km2, preserves a drainage system bound by two major tectonic faults. A quantitative geomorphic analysis of the drainage system reveals 68 catchments, with channel steepness and knickpoint analysis of catchment-hosted paleo-rivers showing that the landscape preserved a >2 Myrs long period of transient tectonics. We interpret that this landscape records punctuated uplift of the footwall of a major rift-related normal fault at the onset of rifting. The landscape was preserved by a combination of relatively rapid subsidence in the hangingwall of a younger fault and burial by post-incision sediments. We show how and why erosional landscapes are preserved in the stratigraphic record, and how they can help us understand the tectono-stratigraphic evolution of ancient continental rifts.