Plume tectonics as a cause of mass wasting on the southeast Greenland continental margin

Abstract

Deposition of sediments on the southeast Greenland shelf is limited by its narrow width, low degrees of tectonic subsidence, and lack of a block faulted basement topography. A marked hiatus on the continental slope, removing the Eocene and Oligocene, together with a late Eocene-early Oligocene hiatus on the continental rise, can be related to mass wasting along the continental slope. Erosion correlates with a phase of rapid tectonic subsidence, caused by relative retreat of the Iceland Plume from the area, affecting the oceanic crust more than the continental shelf. Relative deepening of > 1 km over 10 my steepened the continental slope and triggered erosion. Following the cessation of rapid subsidence, a submarine fan progressively onlapped the continental slope. The lack of a major mid Oligocene erosion surface on the shelf, despite shallow water depths, indicates that the magnitude of the mid Oligocene eustatic sea level fall is much less than the 200m predicted by the Exxon sea level curve.