ALBERT

Description: The Nyk High is an approximately northeast-trending, Late Cretaceous to early Tertiary structural high situated in the western Vøring Basin, offshore Norway. It is defined by a thick sequence of Upper Cretaceous to lower Tertiary sediments that dip toward the southeast and are cut by normal faults with throws up to 1500 m (4921 ft). Across-fault sediment thickness variations and stratigraphic onlap relationships show that these faults were active during Campanian to early Paleocene extension, prior to the separation of Norway from Greenland ca. 55 Ma. Sediments preserved in the hanging walls of these rift-related normal faults are deformed by two populations of folds: one set is oriented clockwise of the fault strike; the other is oriented parallel to the fault strike. Stratigraphic relationships show that both sets of folds formed subsequent to rifting during the latest Paleocene to the earliest Eocene. We interpret these folds as having developed during minor sinistral transpression, which was partitioned between the northeast-southwest sinistral strike-slip reactivation of the normal faults and the northwest-southeast coaxial shortening (folding) within the fault hanging walls. The Nyk High is oriented counterclockwise to the inferred line of the continental breakup. We speculate that transpression was driven by north-northwest forces arising from the differential topography along the incipient plate boundary and the presence of hot, buoyant material beneath this elevated axial region. Such deformation will not necessarily impact significantly on source rock maturity or the distribution of reservoir sands but can give rise to unusual structural trap geometries. It is also likely to increase the connectivity of trap-bounding faults. Jonathan Imber is Statoil Lecturer in Petroleum Structural Geology at Durham University. He received his B.Sc. degree (1994) and his Ph.D. (1998) from Durham before joining the Fault Analysis Group in 1998. He returned to the Reactivation Research Group as a research assistant in 2002. His work is mainly concerned with investigating the growth of faults using three-dimensional (3-D) seismic data.Robert E. Holdsworth, Fellow of the Geological Society (FGS), Fellow of the Geological Society of America, received his B.Sc. degree (Liverpool) in 1981 and his Ph.D. (Leeds) in 1987 and is a professor of structural geology at Durham University. His research includes fault reactivation, digital geological mapping, strain partitioning, and flow kinematics in shear zones. He is founder of the Reactivation Research Group, a cofounder of the Durham Geospatial Visualization Acquisition and Analysis (GAVA) facility, and a director of Geospatial Research Ltd. Ken McCaffrey, FGS (B.Sc. degree, Belfast, 1986; Ph.D., Durham, 1990), is senior lecturer in earth sciences at Durham University. His research interests include the geometric and kinematic evolution of deformation zones, their population dynamics, and geospatial properties. He is a member of the Reactivation Research Group, a cofounder of the Durham GAVA facility, and a director of Geospatial Research Ltd. Robert W. Wilson holds degrees in geological sciences (B.Sc.) and geochemisty (M.Sc.) from Leeds University, United Kingdom. He is currently is a postgraduate research student within the Reactivation Research Group, where he has played a key role in developing new digital geological mapping workflows. His research interests include quantitative fracture analysis and basement reactivation on the northeast Atlantic passive margin. Richard Jones is chief executive officer of Geospatial Research Ltd., a new spinout company based in the University at Durham, United Kingdom, that specializes in the construction of high-resolution digital outcrop models for use as quantitative analogs in reservoir characterization. His research interests include digital mapping, laser scanning, 3-D visualization, and analysis of complex 3-D fold and fault geometries. Richard England is a lecturer in geophysics at Leicester University. His research interests include the applications of seismic and potential field data to the properties and evolution of the continental lithosphere, particularly rift systems, continental margins, and the process of epeirogenesis. He currently supervises research on the velocity structure of Europe and the Ethiopian rift and rifting in Mongolia. Grim Gjeldvik graduated with a master's degree from Oslo University (1997), where his research focused on the structural geology of the Devonian basins in east Greenland. He joined BP Norway in 1998, working initially in exploration and subsequently as a structural geologist in various BP asset teams. He has spent the last 3 years working on BP Norway operated fields.