Climatic cyclicity and accommodation space in arid to semi-arid depositional systems: an example from the Rotliegend Group of the UK southern North Sea

This paper is included in the Special Publication entitled 'Petroleum geology of the southern North Sea: future potential', edited by K. Ziegler, P. Turner and S.R. Daines. The arid to semi-arid, continental deposits of the Permian Rotliegend Group of the UK southern North Sea (SNS) provide an ideal opportunity to test and further the concepts of sequence stratigraphy in fully non-marine depositional systems. Although these depositional systems are detached from the effects of sea-level change, cyclic fluctuations in the climatic regime result in variations in the vertical facies successions laid down. The effects of increasing or decreasing aridity upon depositional processes are considered. Climatic cycles, bounded at the point of lowest aridity are defined. These climatic cycles have been correlated between different, co-existent depositional environments. This enables depositional systems, such as those present in the Rotliegend, to be considered chronostratigraphically. The application of these concepts to an extensive data set illustrates that whilst the internal architectures of sedimentary cycles are controlled by the depositional processes and their positions within the basin, the thickness of the cycles directly reflects the rate of accommodation creation.