Controls on depositional history and architecture of the Oligocene–Miocene succession, northern North Sea Basin Yngve Rundberg and Tor Eidvin The tectonostratigraphic framework of the Oligocene–Miocene succession in the northern North Sea Basin (58–62  N) is closely linked to the large-scale structural evolution of the NW European passive margin. Fairly contemporaneous with the structural doming on the Mid-Norwegian margin uplift activity also affected the Shetland Platform and southern Fennoscandia, including the sedimentary basin of the northern North Sea. This uplift caused a gradual shallowing-upward trend of the northern North Sea Basin, which culminated in severe submarine and possibly also subaerial erosion during middle Miocene, creating a northward increasing stratigraphic break (20 million years in northernmost North Sea), which is visible as a distinct seismic unconformity. Uplift of the East Shetland Platform caused three major phases of sand influx to the basin (1) an early Oligocene phase, resulting in deposition of gravity flow sands in the northern Viking Graben (Statfjord–Tampen area); (2) an early Miocene phase, resulting in deposition of turbiditic sands (Skade Formation) in southern Viking Graben; and (3) a late Miocene–early Pliocene phase, resulting in deposition of shelfal sands (Utsira Formation). During the latter phase, the northern North Sea Basin formed a relatively shallow marine, shelfal strait between deeper marine settings to the north and south. The Utsira Formation sands accumulated in this narrow strait in a high-energy, possibly tidal-current controlled regime. This chapter also presents an improved lithostratigraphic and chronostratigraphic subdivision of the Oligocene–Miocene including redefinitions of the Skade and Utsira formations. The Oligocene–Miocene succession in the northern North Sea has been subdivided into two megasequences, separated by a seismically distinct unconformity (mid-Miocene break). The age diagnostic Bolboforma assemblages, known from ODP/DSDP boreholes in the North Atlantic and on the Vøring Plateau, have aided in correlation between wells and have been important in resolving the basin history. Introduction In this chapter, we present our latest understand- ing of the depositional history of the Oligocene– Miocene succession in northern North Sea. The main object has been to view the depositional history of this area in a larger-scale tectonic perspective. Focus has been on the depositional architecture, stratigraphical outline and the coarse clastic input to the basin, with special emphasis on the Utsira Formation. We also present an improved chronology of the Oligocene–Miocene, with more precise age constraints of the Skade and Utsira formations. The study area embraces the northern North Sea between 58 and 62  N. Some results of the work carried out in the Møre and Faeroe–Shetland Basins are also presented. The erosive mid-Miocene surface forming the top of the Hordaland Group and its continuation to the south has been crucial to our work, and subdivides the strata described in this chapter into two distinct megasequences. Critical features that are preserved in the southern part of the basin are applicable to the interpretation of strata, farther north. This work synthesizes several data sets and methods. The interpretations are results of detailed biostratigraphic works; integrated with 87 Sr/ 86 Sr isotope stratigraphy, seismic and wireline log studies. A suite of regional 2-D lines from an extensive database has been interpreted. Six selected lines are presented in this chapter. An extensive well database has also been available for study. The well data include gamma ray, resistivity and sonic logs; in some wells the density and neutron logs were also available. Interpreted log data from 207 Onshore–Offshore Relationships on the North Atlantic Margin edited by B. Wandas et al. NPF Special Publication 12, pp. 207–239, Published by Elsevier B.V., Amsterdam ß Norwegian Petroleum Society (NPF), 2005