Late Cenozoic sedimentation and uplift history on the mid-Norwegian continental shelf

Abstract

Four Mid(?)/Late Cenozoic sedimentary units are recognised on the mid-Norwegian continental shelf: (1) A thin Miocene unit, (2) a “deltaic complex” variously dated to be of Oligocene or Early Pliocene age; (3) A Late Pliocene-Early Pleistocene low angle prograding unit and (4) a Mid/Late Pleistocene blanketing diamicton. The deltaic complex which extends along the Norwegian coast from the Lofoten Islands in the north to at least 62°45′N, is inferred to be the result of regional uplift of Fennoscandia during Oligocene or Early Pliocene times. As a result of further uplift and regional glaciations during the Late Pliocene-Early Pleistocene, a system of low angle prograding sequences of mainly glacigenic sediments were deposited. Inferred glacial erosional forms suggests periods of grounded ice on the continental shelf. The sedimentary regime was dominated by subglacial sediment input to the shelf edge and later reworking by gravity flows down the continental slope. At first most of the sediments within the study area were derived from the Lofoten area in the northeast. Later the progradation had a more east-west direction. During the Late Pliocene/Early Pleistocene period the shelf edge prograded about 100 km, and an average sedimentation rate of 42 cm/10 3 years is found.