Along-slope variation in the late Neogene evolution of the mid-Norwegian margin in response to uplift and tectonism
Published:January 01, 2002
D. Evans, S. McGiveron, Z. Harrison, P. Bryn, K. Berg, 2002. "Along-slope variation in the late Neogene evolution of the mid-Norwegian margin in response to uplift and tectonism", Exhumation of the North Atlantic Margin: Timing, Mechanisms and Implications for Petroleum Exploration, A. G. Doré, J. A. Cartwright, M. S. Stoker, J. P. Turner, N. White
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As part of the Norwegian Deep Water Programme, a regional geological and geophysical interpretation of the mid-Norwegian margin resulted in the establishment of a late Paleogene to Holocene stratigraphic framework for the margin, and identification and mapping of a range of possible geohazards, including slides. At the Vøring margin in the north, there has been the build-out of a huge prograding wedge of sediment in Plio-Pleistocene times. The sediments of the wedge are assigned to the Naust Formation, which has been subdivided into eight units (A-H), and includes only a few palaeoslides. To the south of the Vøring margin lies the Storegga Slide Complex and the North Sea Fan, and the whole of this southern region shows evidence of several major palaeoslides. The sediments are also referred to the Naust Formation, which here are subdivided into nine units (O-W) that have been partly correlated with equivalent Naust units to the north. The oldest Naust unit in the south, Naust Unit W, is largely made up of slide deposits that provide evidence for the earliest identified large-scale slope instability in the Storegga Slide Complex. This instability was penecontemporaneous with the initiation of the prograding wedge to the north, and both features are postulated to be the result of uplift of the Norwegian mainland. In the case of the Storegga Slide Complex, which lies close to the main area of uplift, oversteepening of the margin, together with seismicity associated with the Jan Mayen Fracture Zone and Møre-Trønderlag Fault Complex, may have initiated sliding that has since occurred intermittently up to Holocene times, over a time interval when there has additionally been much glacio-isostatic movement.
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Exhumation of the North Atlantic Margin: Timing, Mechanisms and Implications for Petroleum Exploration
Northwest Europe has undergone repeated episodes of exhumation (the exposure of formerly buried rocks) due to such factors as post-orogenic unroofing, rift-shoulder uplift, hotspot activity, compressive tectonics, eustatic sea-level change, glaciation and isostatic readjustment. The main observational legacy of this exhumation around the North Atlantic is preserved in the comparatively young (Mesozoic and Cenozoic) geological record of this region. Despite a rapid increase in the understanding of the exhumation of this area, there are still many unknowns: the relative intensity of the various phases and their geographical variation; mechanisms of uplift; primary causes of exhumation. Tied to these problems is the larger-scale question of whether the circum-North Atlantic is unique or whether its behaviour is typical for passive margins.
There have been several attempts in recent years to bring together researchers to address these questions, but these have often focused on one particular geographical area or one particular exhumation phase. Before an integrated story can emerge, disciplines that have traditionally remained apart need to come together: geomorphology and offshore seismic interpretation; Palaeogene and Neogene studies; Scandinavian and British-Irish research schools. This volume represents a first step in this direction by providing an inter-disciplinary set of studies over a wide latitudinal range of the NW European margin.
The studies presented here are based on a variety of techniques that have been employed to address the main concerns of North Atlantic exhumation history, including timing, mechanisms and the sedimentary response of the continental margin. The 25 papers presented in this volume have been arranged in four sections to reflect the highly varied approach to this subject and the commercial implications. Part 1 is concerned with exhumation mechanisms, focusing primarily on the Iceland Plume. Parts 2 and 3 present ongoing research on the continental margin record offshore Scandinavia, Britain, Ireland and the Faroes. The papers in these two parts illustrate the communication that is now occurring between the two regional research schools and the acknowledgement of a multiphase Cenozoic denudation chronology for both areas. Part 4 contains five papers describing the significant changes to the hydrocarbon systems that occur in exhumed basins, detailing the implications for hydrocarbon-bearing basins.
Exhumation of the North Atlantic Margin: Timing, Mechanisms and Implications for Petroleum Exploration is the most up-to-date and complete volume integrating all aspects of the Mesozoic-Cenozoic exhumation of North Atlantic borderlands. Itwill be of interest to those within the oil industry, geomorphologists and other workers with an interest in NW European regional geology.