Late Quaternary geological development of the Jutland Bank and the initiation of the Jutland Current, NE North Sea

Abstract

Using shallow seismic and core data, a reconstruction has been made of the Late Pleistocene-Early Holocene palaeogeography of Jutland Bank, NE North Sea. A division of Late Pleistocene and Holocene deposits into five sequences has been proposed for the study area: W5 representing the Pleistocene glacially deposits; W4 infilled channels incised into W5; W3 a composite, unspecified sequence of late-glacial glaciolacustrine\/glaciomarine origin and\/or deposits older than Boreal; and W1 and W2 representing the Holocene Jutland Bank Sand Unit. The seismic stratigraphy of the northwestern part of the study area reflects different stages of the Holocene transgression. A paleocoastline situated 15 km off the present Danish North Sea coast existed during the Early Holocene in connection with a protected marine environment where the Agger Clay Unit was deposited to the east. From investigations of the mollusc fauna it has been shown that simultaneous with the Agger clay deposition an open marine environment with a Boreal molluscan fauna was present in the north- western part of the study area. An archipelago-like structure of emerging morainic islands on the Jutland Bank has been obstructive for establishing any long-shore currents. Tidally induced currents were the dominating sediment transport mechanism until flooding finally drowned the archipelago in the Mid Holocene.