A regional net erosion map for the greater Barents Sea shows that the different areas in the Barents Sea region have been subject to different magnitudes of uplift and erosion. Net erosion values vary from 0 to more than 3000 m. The processes have important consequences for the petroleum systems. Reservoir quality, maturity of the source rocks and the migration of hydrocarbons are affected by the processes. Owing to changes in the PVT conditions in a hydrocarbon-filled structure, uplift and erosion increase the risk of leakage and expansion of the gas cap in a structure. Understanding of the timing of uplift and re-migration of hydrocarbons has been increasingly important in the exploration of the Barents Sea.

Palaeogeographic and tectono-stratigraphic considerations in the greater Barents Sea show that the distribution of reservoirs and hydrocarbon source rocks from the Late Palaeozoic to the Palaeogene can be related to three tectonic phases. Firstly, the Palaeozoic Caledonain Orogeny caused uplift to the west, followed by eastward sediment distribution across the shelf, towards carbonate platforms to the east. Secondly the Late Palaeozoic-Mesozoic Uralide Orogeny induced uplift to the east, causing widespread clastic deposition and reversal of the sediment distribution pattern. Thirdly, major Late Mesozoic-Cenozoic rifting and crustal breakup in the western Barents Sea led to the current basin configuration. Reservoir rocks comprise Late Palaeozoic carbonates and spiculites, Mesozoic terrestrial and marine sandstones and Palaeogene deep-water sandstones. Hydrocarbon source rocks range in age from Silurian to Early Cretaceous, and are grouped into three petroleum systems derived from Late Palaeozoic, Triassic and Late Jurassic source rocks. Multiple tectonic episodes caused formation of a variety of trap types, of which extensional fault blocks and gently folded domes have been the most prospective. Volumetric considerations of generated petroleum indicate that charging is not a limiting factor, except in the western margin.

The concept of stratigraphic base level, or the ratio between accommodation and sediment supply (A/S ratio), has been used to analyse the Rusty and Canyon Creek Members of the Campanian Ericson Sandstone in the Rock Springs Uplift, SW Wyoming, USA. The Ericson Sandstone was deposited under fluvial to estuarine conditions in a foreland basin setting influenced both by Sevier‐style (thrust belt) tectonism and by more local, Laramide‐style, foreland uplifts. The depositional setting was situated several tens to a few hundred kilometres from the nearest shoreline. Therefore, sea level change at the contemporaneous shoreline probably had little, if any, influence on the development of the sedimentary architecture. The Rusty Member shows an alternation between incised valleys filled by multi‐storey estuarine channel sandstones showing palaeoflow to the south and delta plain sediments with single‐storey channels with no evidence of tidal influence, which show palaeoflow to the east. This cyclicity is interpreted as recording repeated uplift of the Wind River Range to the north, causing valley incision and reduction of the A/S ratio. During quiescent periods, the A/S ratio increased allowing the valleys to fill and delta plain conditions to be subsequently re‐established because of increased sediment supply from the thrust belt in the west. A regional unconformity at the base of the Canyon Creek Member truncates the Rusty Member, and represents a significant reduction of the A/S ratio caused by Laramide tectonic uplift. The Canyon Creek Member is a multi‐storey, multi‐lateral fluvial channel sandstone, where channel preservation and thickness increase upwards, suggesting an increase of the A/S ratio. The Canyon Creek Member channels are interpreted to have been sinuous, meandering channels from the observed sedimentary structures and fill patterns, despite their sand‐rich nature. It is argued that grain size is a poor indicator of channel planform, and that there was very low preservation potential for fine material because of a relatively low A/S ratio. The top of the Canyon Creek Member is a regionally correlative surface marking an abrupt increase of the A/S ratio. This surface is termed an expansion surface, denoting an abrupt increase in accommodation. The overlying Almond Formation shows a single‐storey alluvial architecture with a very high preservation of fine‐grained material. An assumed correspondence in time of the Late Absaroka thrust phase in the Sevier belt to the west and the formation of the sharp top of the Canyon Creek Member suggests that the thrust phase caused a basin‐wide abrupt increase of subsidence that changed the alluvial architecture. As an alternative to sequence stratigraphic nomenclature defined for strata controlled by shoreline movements, a scheme relating systems tracts and surfaces to changes in stratigraphic base level is proposed. Such a scheme is useful where correlations to shoreline strata are ambiguous or cannot be made, or where tectonics and climate are important controls.

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The occurrence of Triassic to early Jurassic mudstone and sandstone sequences in the northern North Sea basin, and their possible significance in terms of basinal subsidence pattern is reviewed. The latest phase (Scythian) in a period of crustal stretching is illustrated from the Horda Platform where block rotation has been accompanied by infilling (>2000 m) of alluvial deposits in a series of N-S oriented, asymmetric sub-basins.The 'post-rift' succession is subdivided into three megasequences which, in their broad areal development over most of the northern North Sea basin, contrast with the rift-infill sequences. The late Scythian-Ladinian megasequence (PRI) documents an early phase of widespread, fine-grained, floodbasin deposition which was interrupted by prograding, sandy sheetflood lobes (Tcist Fm). The latter were derived from marginal alluvial fan bajadas along the Norwegian hinterland and from certain segments of the East Shetland uplands. This phase of infilling culminated with basinwide, sand deposition (Lomvi Fm) from amalgamated fans and braided river systems. Although classified as 'post-rift', mcgasequcncc PR1 does show some 'growth' along the older rift lineamcnts.The Carnian-early Rhactian megasequence (PR2) records rctrogradation of the earlier sandy systems towards the basin margins (lower Lundc Fm) followed by rcncwcd establishment of extensive lacustrine and coastal floodbasin conditions (middlc Lundc Fm.). Low-lying tracts within thc northcrly floodbasins allowcd influx of brackish lagoonal waters from a sea to the north. The scqucncc culminates with repeated progradation of cxtcnsivc sandy alluvial plains (lower and middle parts of upper Lundc Fm).The early Rhaetian-Sinemurian mcgasequencc (PR3) also records retrogradation of the earlier sandy fluvial systems (middle to upper parts of uppcr Lundc Formation), followed by thc development of cxtensivc, fine-grained floodbasins and occasional brackish-marine lagoons (uppcrmost Lundc Fm.) into which isolated sandy streams and fan deltas progradcd from both East Shetland and Norwegian margins. Subscqcunt progradation of streams and fan systems eventually allowed the dcvclopmcnt of northward, through-flowing, axial river systems (Statfjord Fm). Thcrc arc clcar signs of morc active intra-basinal tectonics during this third stage in the basin's post-rift history, with latest Triassic-earliest Jurassic depoccntres tending broadly to occupy the sites of the future Viking and Sogn Grabcns.In the central North Sea the three-fold megasequence development cannot easily bc recognized, though broadly time-equivalent units can bc identified. The carliest phase was dominated by inland floodbasin deposition (Smith Bank Fm.) but this was rcplaccd towards the Norwegian hinterland by, at first, lacustrine/lagoonal and inland sabkha deposition, and later, by sandy alluvial fan development (Skagcrrak Fm.). The sccond phase was dominated by sandy alluvial deposition in the northern and eastern reaches but became muddy floodbasin-dominatcd farther west. The latest ph...