Downloaded from http://sp.lyellcollection.org/ by guest on September 28, 2021 Integrated Basin Studies- Dynamics of the Norwegian Margin: an introduction ARVID NOTTVEDT Norsk Hydro Research Centre, N-5020 Bergen, Norway Present address. Norsk Hydro Canada, l ll-5th Avenue SW, Calgary AB, T2P 3 Y6, Canada Several lithospheric and upper crustal processes theless, the Voring margin is among the best interact in the formation of rift basins and studied volcanic margins globally due to a evolution of such basins into passive margins. regional coverage of multichannel seismic lines, Similarly, the fillings of rift basins depend on a expanded spread profiles and other geophysical variety of tectonic, morphological and sedimen- and geological data. In addition, the successful tary processes. Areas that have passed through scientific drilling through a sequence of sea- a complete evolution from intra-cratonic rift- ward dipping reflectors on the Voring Plateau ing through breakup and passive margin forma- has greatly contributed to the understanding tion offer particular opportunities to study and of the margin. link the different processes of basin formation This setting makes the study region an and filling. One such area, that has a unique excellent laboratory in which to study progres- combination of a well-preserved rock record and sive rift evolution and its inter-relationship with abundant data, is the Norwegian North Sea- basin formation and filling, including the inter- North Atlantic margin, herein referred to as plays between structural evolution, erosion, the Norwegian margin. sedimentation and magmatism, on both regional During post-Caledonian times the North Sea and local scales. Consequently, the region allows and mid-Norwegian margin underwent several research into fundamental earth processes, which episodes of lithospheric extension (multi-phase also have direct implications for hydrocarbon rifting), of which the latest led to crustal break- exploration and assessment. up and accretion of oceanic crust between Norway and Greenland near the Paleocene- Eocene transition. Prominent pre-breakup exten- sional episodes, in late Permian-Triassic, late The Integrated Basin Studies (IBS) project Jurassic, early Cretaceous and mid-Cretaceous time, led to the development of the North Sea The papers and research results presented here rift system, the large Cretaceous Voring and have been prepared as part of the Integrated More sedimentary basins off Norway, and con- Basin Studies project (Fig. 1).This project was jugate equivalents off eastern Greenland. Latest funded under the DG IIX, JOULE II pro- Cretaceous-Paleocene rifting and breakup were gramme, with the objective to study the litho- accompanied by large-scale igneous activity, spheric and upper crustal processes governing developing the present conjugate volcanic mar- the formation and evolution of extensional and gins of the North Atlantic. foreland basins and to decipher the role of The North Sea, in particular, is covered with tectonics, sea-level and sedimentary processes in an exceptionally good geological and geophysi- the filling of such basins. As part of this task, the cal industry and academic database, comprising project also aimed at studying the physical laws both high-quality geophysical profiles and a of compaction in fine-grained sediments. Based large number of industrial wells. About 30 years on these results, a new generation of descriptive of active exploration in the North Sea has led to as well as numerical basin formation and basin an advanced level of understanding of the geo- fill models has been derived. logical evolution and complexity of the basin. Results from the Integrated Basin Studies Numerous papers have been published on the project have been reported in an extensive Final formation and filling of the North Sea intra- Report to the DG IIX, and selected papers cratonic rift structure. prepared within Modules 1 and 2 have been The mid-Norwegian margin has a less exten- published in two previous Geological Society sive, but increasing, industry database. Never- Special Publications, nos 134 and 156. From: NOTTVEDT, A. et al. (eds) Dynamics of the Norwegian Margin. Geological Society, London, Special Publications, 167, 1-14. 1-86239-056-8/00/$15.00 ~ The Geological Society of London 2000. Downloaded from http://sp.lyellcollection.org/ by guest on September 28, 2021 2 A. NOTTVEDT This book has been prepared with the inten- Thematicalh', the project module focused on tion to give a representative picture of the sci- three related themes: (i) Intra-plate rifting and entific span and results of the project Module 3: basin formation, (ii) Basin infill and (iii) Con- Dynamics of the Norwegian Margin. It includes jugate volcanic margins. The data coverage and papers prepared by PhD students funded geological setting resulted in a topical focus on directly through the project, as well as papers two geological provinces, the northern North Sea written by researchers in academia and industry and the Norwegian-Greenland Sea rifted volca- that have been working in, or closely associated nic margins. The More Basin, on the volcanic with, the project. More margin, links these two provinces. Geo- graphically, the two former research themes (Intra-plate rifting and basin formation and IBS Module 3: Dynamics of the Norwegian Basin infill) focused on the northern North Sea Margin (IBS-DNM) and the More Basin, while the latter (Conjugate volcanic margins) primarily dealt with the More- The Integrated Basin Studies project Module 3, Voring margins and their conjugates. Dynamics of the Norwegian Margin (Fig. 2), was Of particular interest in the intra-plate setting technically part of the IBS project, but received is the kinematics and relative importance of funding directly from the Research Council of deeper versus shallow crustal processes and how Norway (RCN). The module was coordinated by these control overall subsidence patterns; the Norsk Hydro, and contractual arrangements erosional and provenance history of sediment were made between Norsk Hydro and EU, supply areas: and the architecture, composi- Norsk Hydro and RCN, and Norsk Hydro and tion and history of basin fill. The work con- partners. The module was organized into three centrated on syn-rift basin fill, but included also themes and subordinate topics (Fig. 3). post-rift strata. It has been attempted to estab- lish general and coupled models for rift basin Research objectives formation and sediment filling in the northern North Sea. The scope of the IBS-DNM project module was The Norwegian-Greenland Sea represents to analyse and model the dynamics of the basins complete extension and thinning of the litho- off mid-Norway and in the northern North Sea, sphere. Therefore, the margin basins bear an in order to establish a better understanding of the imprint not only of the same events as the processes controlling basin formation and filling intra-plate basins, but have also undergone and to develop new models for multiphase, a structural, magmatic and depositional his- intraplate rifting and volcanic margin formation. tory reflecting the formation and subsequent Projects Modules INTEGRATED ~Tertiary Extension within'~ BASIN STUDIES theAIpine Orogen ) Cenozoic Foreland STRATIGRAPHIC Basins of W. Europe MODELLING Dynamics of the Norwegian Margin STRUCTURAL IMAGING ( Compactionand Fluid ~ Flow in f-g sediments RESERVOIR Modelling 1 ENGINEERING IBS Co-ordinating Team: B.Durand, Institut Francais du Petrol S.Cloetingh, Vrije Universiteit Amsterdam C.Puigdefabregas, Servei Geologic de Catalunya Fig. 1. DG IIX: Joule II Geoscience II Programme Downloaded from http://sp.lyellcollection.org/ by guest on September 28, 2021 INTEGRATED BASIN STUDIES 3 development of the present volcanic passive It is important, therefore, that the project had margin. To understand the basin evolution and access to much of the existing seismic, structural tectono-magmatic history it is necessary to and stratigraphic framework in the study region assess the timing and magnitude of the different to define and select the optimal target areas for tectonic, magmatic and subsidence episodes for the detailed studies described in the various the various basins. In order to determine the project topics. The industrial partners were style of deformation for each tectonic episode instrumental in achieving this objective. and to quantify the magnitude of crustal and The work on crustal structure and basin lithospheric extension, restoration of the struc- formation concentrated around seven transects turally defined extensional deformation through from the northern North Sea to the Voring time was particularly emphasized. margin (Fig. 4), whereas the topic on stress field covers the entire Norwegian continental shelf. The syn-rift infill studies focused on selected Database and methods fault-blocks in the northern North Sea, whereas the post-rift (Cenozoic) infill studies integrated The project database (Fig. 4) consisted of data from the Danish and Norwegian sectors scientific deep reflection and refraction seismic of the North Sea, up to 62°N. The work on data, large volumes of industry regional 2D erosion and provenance included the northern reflection seismic data, 3D seismic data, well North Sea. The studies on volcanic margins data, potential field data, industry special concentrated on the mid-Norwegian margin, but studies and reports, in addition to published comparative studies were made with other vol- literature. canic margins