Multidisciplinary studies in the Netherlands have revealed two new phases of late Variscan extensional faulting during the Late Permian. The names Tubantian I and II are proposed in this paper. Tubantian I movements were triggered by rapid deposition and loading of anhydrite upon a differentiated basement, in combination with mild E-W extension. A series of small pull-apart basins and tilted fault blocks formed and local collapse occurred of the Variscan Front. The relief was subsequently filled with carbonates and evaporites of the Z1 (Werra) Formation. Fault movements stopped prior to deposition of the Z2 (Stassfurt) Formation. Tubantian II movements caused uplift and erosion, especially in the southern onshore Netherlands. Contemporaneously, sandy erosional products were deposited in the southwestern offshore area of the Netherlands and the adjacent UK sector and playa-type halites and claystones accumulated in the central parts of the basin. Three features have implications for hydrocarbon exploration: the early formation of fault/dip closed structures shortly after deposition of the Upper Rotliegend; the reorganization of the fluid-flow system and the deposition of contemporaneous sandy deposits.
- GeoRef, Copyright 2004, American Geological Institute.