Abstract This paper considers the lithospheric structure and evolution of the wider Barents–Kara Sea region based on the compilation and integration of geophysical and geological data. Regional transects are constructed at both crustal and lithospheric scales based on the available data and a regional three-dimensional model. The transects, which extend onshore and into the deep oceanic basins, are used to link deep and shallow structures and processes, as well as to link offshore and onshore areas. The study area has been affected by numerous orogenic events in the Precambrian–Cambrian (Timanian), Silurian–Devonian (Caledonian), latest Devonian–earliest Carboniferous (Ellesmerian–svalbardian), Carboniferous–Permian (Uralian), Late Triassic (Taimyr, Pai Khoi and Novaya Zemlya) and Palaeogene (Spitsbergen–Eurekan). It has also been affected by at least three episodes of regional-scale magmatism, the so-called large igneous provinces: the Siberian Traps (Permian–Triassic transition), the High Arctic Large Igneous Province (Early Cretaceous) and the North Atlantic (Paleocene–Eocene transition). Additional magmatic events occurred in parts of the study area in Devonian and Late Cretaceous times. Within this geological framework, we integrate basin development with regional tectonic events and summarize the stages in basin evolution. We further discuss the timing, causes and implications of basin evolution. Fault activity is related to regional stress regimes and the reactivation of pre-existing basement structures. Regional uplift/subsidence events are discussed in a source-to-sink context and are related to their regional tectonic and palaeogeographical settings.

Abstract In the North Atlantic, Laurentia–Eurasia break-up commenced in the Late Carboniferous, largely following the structural grain of the Caledonian Fold Belt. However, in the Arctic region, a 45° offset in the plate boundary between North Greenland and Svalbard was determined by a number of pre-Caledonian fundamental faults in North Greenland. As a result, this segment of the plate boundary experienced significant episodes of combined transtension and transpression, in part controlled by the movement of a temporarily independent Greenland Plate. Late Permian–Mesozoic deposits in the North Greenland Wandel Sea Basin record the plate-boundary history along this offset, in our view in a series of at least 20, variously disturbed, pull-apart basins, most of which can be assigned to four major episodes of pull-apart basin formation. The direction of the pre-existing fundamental faults, in combination with the regional variation in rock properties of both the basin floor and basin fill, explains the marked differences in tectonic style recorded along the plate boundary.

Outcrop and subsurface data from the central northern margin of the Pangean shelf in North Greenland, Svalbard, and the Norwegian Barents Sea record the depositional response of a Northern Hemisphere subtropical shelf to Late Carboniferous–Early Permian (Bashkirian–Sakmarian) Gondwana glaciations. The dominant motif is that of meters to tens of meters of exposure-capped cycles of carbonates, mixed carbonates, and siliciclastics and, in older stratigraphic levels, siliciclastics and gypsum. Halitegypsum-carbonate cycles developed in deeper, isolated basins. Individual cycles of carbonate and mixed carbonate-siliciclastics reflect deposition during the later stages of transgression, sea-level highstands, and high-frequency and high-amplitude glacioeustatic sea-level fluctuations. The Moscovian sections in North Greenland are composed of 43 such cycles, each of which apparently reflects sealevel fluctuations linked to the 100 k.y. Milankovitch cycle. The stratigraphic distribution of subaerial exposure surfaces indicates that during Late Carboniferous–Early Permian time, the northern Pangea shelf repeatedly changed from being a shallow subtropical carbonate platform to a vast subaerially exposed carbonate plain, and it implies sea-level amplitudes in excess of 50 m. A major Gondwana deglaciation event is recorded in early Sakmarian shelf successions offshore northern Norway, where rapid flooding led to sediment starvation over an extended period of time, and when sedimentation finally resumed, the cyclic motif is absent.

The crystalline basement within the northern parts of the Caledonian orogen, and in the adjacent foreland, is overlain by a several-kilometer-thick succession of sedimentary and volcanic rocks, the Paleoproterozoic–Mesoproterozoic Independence Fjord Group and the Mesoproterozoic Zig-Zag Dal Basalt Formation. The lowermost strata of the Independence Fjord Group, composed of quartzitic and feldspathic sandstones and conglomerates with interbedded volcanic rocks, occur within the Caledonian orogen and are strongly deformed. These strata were deposited around 1740 Ma ago, and they were associated with a period of rifting that succeeded a long sequence of Paleoproterozoic orogenic events. Similar sandstones, interbedded with siltstone units but without volcanic rocks, are widespread in the Caledonian foreland, where they are virtually undeformed. These foreland deposits were laid down in a continental sag basin under semiarid conditions. Sedimentary structures indicate a largely fluvial origin, with intermittent eolian transport. The siltstones were deposited in extensive shallow lakes. Desiccated bedding surfaces show that these periodically dried out. The sandstones of the Independence Fjord Group are cut by a multitude of doleritic sheets and dikes, the ca. 1380 Ma Midsommersø Dolerites, and more silicic intrusions, most of which show evidence of hydrothermal alteration and variable contamination with components derived from the crystalline basement and the sandstones. Some intrusions consist almost entirely of crustally derived material. The Zig-Zag Dal Basalt Formation conformably overlies the Independence Fjord Group. Compositional similarities suggest a genetic relationship with the Midsommersø Dolerites, but the basalts appear to be less crustally contaminated. The basalts were deposited within a basin that underwent subsidence during and after volcanic activity. The Zig-Zag Dal Basalt Formation is unconformably overlain by Neoproterozoic sedimentary successions. The unconformity represents a stratigraphic hiatus of some 500 m.y., for which no information is available from North Greenland.