Middle to Late Jurassic basin evolution and sandstone reservoir distribution in the Danish Central Trough. A contribution to the EFP-90 project: Upper Jurassic sandstone reservoirs in the Danish Central Trough

摘要

During the Middle and Late Jurassic, long-term eustatic sea-level rise and halfgraben subsidence in the Danish Central Trough resulted in a major transgression. Deposition of widespread alluvial plain sediments in the Soegne Basin and Tail End Graben was terminated in the Late Bathonian due to bypass and erosion following a short-term relative sea-level fall. The sea-level fall was followed by a relative sea-level rise during the Callovian which caused the development of a transgressive succession of coastal plain and shallow marine deposits. The transgressive succession consists of several prograding sediment wedges commonly terminated by a coal bed and a flooding surface. As transgression continued during the Late Jurassic, the shoreline shifted westwards. Transgressive Oxfordian shoreface to back-barrier sandstone were deposited. Another short-term relative sea-level fall occurred during the Kimmeridgian during which regressive shoreface to beach sandstones were deposited. During the Late Kimmeridgian and Volgian, the long-term relative sea-level rise resulted in deposition of thick Volgian offshore claystones in the central part of the Central Trough (Heno Plateau, Gertrud Graben and Feda Graben). During the Volgian and Early Cretaceous, the transgression continued towards the west, and shallow marine sandstones may have been deposited along the western margin of the Central Trough fringing the Mid North Sea High (Grensen Nose Basin and Outer Rough Basin). Along the Ringkoebing Fyn High in the easternmost part of the Central Trough, Volgian and Early Cretaceous fan-delta sandstones and basin floor turbidite sandstones are interstratified with offshore claystones. (au) (22 refs.).