The sedimentology of lower-slope clastic successions in deep-water environments

Interest has been stimulated by discovery of hydrocarbons in turbiditic sandstones interpreted as submarine slope deposits. The aim of this study is to test models of slope development, and to document the variety of gravity flow processes and products within deep-water lower-slope regions. This has involved a comprehensive sedimentological study of the geometry, facies distribution and spatial and temporal variation of internal architectural elements within deep-water clastic successions from three study areas. The Maras Foreland Basin (Miocene) contains an exhumed deep-water slope succession. Two laterally equivalent intervals highlight the complex lateral facies transitions that occur in lower-slope regions. The Macduff Slate Formation (Cambrian/Ordovician) was deposited in a deep-water passive margin environment and contains associated glacial deposits. Following deposition the sediments experienced several phases of regional metamorphism and associated deformation. A detailed structural and sedimentological study of several laterally equivalent intervals determined that the sediments were deposited in a sinuous, aggradational channel system with associated levee-overbank elements. Six age-equivalent cored reservoir intervals, offshore Côte d’Ivoire, West Africa (Cretaceous) were deposited on a submarine slope during late syn-rift extension. A comprehensive sedimentological study complimented by petrophysical and seismic data determined that deposition occurred within a series of stepped mini-basins or tilted fault blocks. There is evidence that the basins did not fill uniformly and that fault activity during sedimentation controlled sediment distribution patterns across faults, intervening transfer zones and within fault blocks. The three study areas differ in age, basin type, grain-size range and the interpreted length and geometry of the shelf-to-slope profile, but contain comparable facies associations linked to depositional architectural elements predicted by models of lower-slope successions.EThOS - Electronic Theses Online ServiceGBUnited Kingdo