Research paper Regional constraints of the Sørkapp Basin: A Carboniferous relic or a Cretaceous depression? I. Anell a, * , A. Braathen a, b , S. Olaussen a a Department of Arctic Geology, UNIS e The University Centre in Svalbard, Postbox 156, 9171 Longyearbyen, Norway b Department of Geosciences, University of Oslo, Sem Sælands vei 1, 0371 Oslo, Norway article info Article history: Received 2 April 2013 Received in revised form 19 December 2013 Accepted 27 February 2014 Available online 12 March 2014 Keywords: 2D seismic Barents Sea Sørkapp Basin Sedimentation abstract The Sørkapp Basin (NW Barents Shelf) contains a comprehensive sedimentary succession that provides insight into regional tectonics and depositional development of the shelf from the Devonian to the Cretaceous. With its location east of the mid-Atlantic spreading ridge and south of Svalbard, the Basin serves as an important link between the offshore and onshore realms. This study subdivides this sparsely studied basin into six main seismic units (three Paleozoic and three Mesozoic). A metamorphic basement together with assumed Devonian sedimentary deposits form the foundation for a chiefly Carboniferous basin. The Basin forms a syncline with infill showing limited fault- influence. Overlying the early infill are Late Carboniferous deposits which show less lateral variation in thickness but also active growth on the few faults showing significant displacement. The overlying platform deposits of the latest Carboniferous and Permian show a change in depositional geometry, with onlapping deposits towards the east probably resulting from uplift of the Stappen High and regional flooding. Subsequent, particularly Late, Triassic sedimentation shows a more distinctly progradational pattern with a dominantly southeastern source for sediments. During this shallow shelf-filling stage, the Sørkapp Basin is sheltered by the Gardarbanken High, blocking the Early Triassic clinoform development. The High was transgressed in the Middle Triassic and the platform-edge progressively approached the present Svalbard coastline. The youngest Mesozoic unit forms a separate saucer-shaped depocenter west of the Sørkapp Basin, where deposits are truncated by the seafloor in a mid-basin position and across the Gardarbanken High. The depositional pattern for this succession correlates with the outcrop pattern of the Adventdalen Group implying a post Middle Jurassic to Cretaceous age. The Sørkapp Basin has been referred to as a Cretaceous feature based in this depocenter. However, the foundations are much older and the Creta- ceous depression is located west of the deeper basin. Accordingly, we propose the informal term Sørkapp Depression for the Cretaceous basin. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction The Sørkapp Basin is a small but up to 4 s deep depocenter on the northern Barents Shelf located between 75  e76  N and 21  30 0 e 25  E(Gabrielsen et al., 1990). It is situated on the Svalbard Platform and enclosed by Spitsbergen, the Edgeøya Platform, and the Stap- pen and Gardarbanken highs (Figs. 1 and 2). There is a narrow shallow strait in the south adjoining it to the Bjørnøya Basin. The Sørkapp Basin, informal, is said to have been named by Rønnevik et al. (1982a,b) (Gabrielsen et al., 1990). However, Rønnevik et al. (1982a,b) make no reference to the Basin in the text, although it is shown on seismic data and drawn as faulted upper Devonian base with drapes of relatively shallow Carboniferous, Permian and Triassic sediments. It appears the term Sørkapp Basin is officially proposed in a study of nomenclature (Gabrielsen et al., 1984), where the first identification of the Basin, then termed the Hopen Basin, is also provided (Faleide and Gudlaugsson, 1981). Referring to the Sørkapp Basin as being one of the ‘best defined features’ within the Svalbard platform area appears to be one of the first published uses of the name in text (Elverhøi et al., 1988), although around the same time other publications also make use of the name (Johansen et al., 1988; Max and Ohta, 1988). The Sørkapp Basin is later mentioned in passing by several studies (Breivik et al., 2005; Grogan et al., 1999; Nøttvedt et al., 2008; Skilbrei, 1991; Worsley, 2008). It is commonly drawn on maps showing various * Corresponding author. Tel.: þ47 79023322, þ47 91182817; fax: þ47 79 02 33 01. E-mail addresses: Ingrid.anell@gmail.com, Ingrida@unis.no (I. Anell). Contents lists available at ScienceDirect Marine and Petroleum Geology journal homepage: www.elsevier.com/locate/marpetgeo http://dx.doi.org/10.1016/j.marpetgeo.2014.02.023 0264-8172/Ó 2014 Elsevier Ltd. All rights reserved. Marine and Petroleum Geology 54 (2014) 123e138