Development of the Permo-Triassic succession in the basin fringe area, southern Netherlands

Abstract

During the Permian, the fringe area of the Southern Permian Basin formed a platform attached to the LondonBrabant Massif. During the Triassic the platform was transformed into basins with differentiated subsidence. Upper Rotliegend sandstones have a much wider distribution than previously recognized. The Rotliegend deposits are capped by sandstones, claystones and carbonates of the Late Permian Zechstein Group. An important feeder system of clastics from the London-Brabant Massif was active in the present-day offshore area of the Netherlands. In the course of time, the location of major sandstone deposition shifted westward. Deposition of the Triassic Buntsandstein was governed by the development of a large feeder system which transported clastics from the Vosges in NE France northward through the Roer Valley Graben and West Netherlands Basin into the Off Holland Low. Influx of coarse clastics ceased during the Middle Triassic. The feeder system was responsible for the deposition of the gas-bearing sheet sandstones of the Volpriehausen, Detfurth and Hardegsen Formations. The importance of the Triassic play is demonstrated by the over 100 x 109 m3 Gas Initially In Place (GIIP) that were discovered since 1968. Subtle unconformities characterize the base of the Volpriehausen and especially the Detfurth Formation. These formations are separated by a regional unconformity from the overlying sandstones and claystones of the Solling Formation, and the claystones, evaporites and sandstones of the Rot Formation. The Muschelkalk Formation consists of shallow marine carbonates and claystones which are interbedded with evaporites. Rock salt was deposited in the Central Netherlands Basin and locally in other areas. Extension during the Late Triassic led to uplift and erosion. After the extension ceased, the upper part of the Keuper Formation was deposited unconformably upon sediments of the Muschelkalk or Rot Formations.