Bounding surfaces in a mixed aeolian-fluvial system (Rotliegend, Wessex Basin, SWUK)

The Dawlish Sandstone Formation is a Late Permian succession of mixed aeoli an and fluvial deposits in the Wessex Basin (SW En,oland). It is used to il lustrate two contrasting types of fluvial/aeolian bounding surface (planar and incised). Planar bounding surfaces separate tabular bodies of fluvial c onglomerate and aeolian dune sandstone. They were produced primarily by win d scour to groundwater table, with the later emplacement of conglomerates r esulting in local fluvial erosion of cemented aeolian dune sandstones. Inci sed bounding surfaces were produced by fluvial downcutting. The erosive rel ief was infilled with mixed aeolian/fluvial deposits. The Dawlish Sandstone Formation may provide the first outcrop example of these incised valley fi lls, which have recently been identified as a major component of the subsur face Rotliegend in the Southern North Sea Basin. The potential variability of aeolian/fluvial sedimentary architecture has important implications for well-to-well correlation and reservoir modelling. (C) 2001 Elsevier Science Ltd. All rights reserved.