Deltaic sedimentation during the Jurassic in the Norwegian-Danish Basin (North Sea)

Abstract

In the Norwegian-Danish Basin, several minor Middle to Late Jurassic deltas (Haldager Formation) were built out from the different highs, which acted as local sediment source areas. The cores studied fromwell 8/3-1 most probably represent the Middle Jurassic Haldager Formation, while wire-line logs and mineralogical composition indicate that the 17/4-1 core may represent the Late Triassic/Early Jurassic Gassum Formation. The analysed sediments of wells 8/3-1 and 17/4-l were deposited in delta-front environments, probably as distributary mouth bars. While the 17/4-1 delta had the Utsira High as a major sediment source area, the 8/3-1 delta material was mainly derived from the Sele High. The composition of the Oxfordian marginal-marine deposits of 16/9-1 indicates both the Utsira and Sele Highs as important source areas, reflecting derivation of sediments by reworking of underlying formations. The studied Oxfordian sandstones of well 16/9-1. may represent sandy equivalents to the Egersund Member of the Bream Formation.