Four Mesozoic–Cenozoic palaeothermal episodes related to deeper burial and subsequent exhumation and one reflecting climate change during the Eocene have been identified in a study of new apatite fission‐track analysis (AFTA®) and vitrinite reflectance data in eight Danish wells. The study combined thermal‐history reconstruction with exhumation studies based on palaeoburial data (sonic velocities) and stratigraphic and seismic data. Mid‐Jurassic exhumation (ca. 175 Ma) was caused by regional doming of the North Sea area, broadly contemporaneous with deep exhumation in Scandinavia. A palaeogeothermal gradient of 45 °C km−1 at that time may be related to a mantle plume rising before rifting in the North Sea. Mid‐Cretaceous exhumation affecting the Sorgenfrei–Tornquist Zone is probably related to late Albian tectonic movements (ca. 100 Ma). The Sole Pit axis in the southern North Sea experienced similar inversion and this suggests a plate‐scale response along crustal weakness zones across NW Europe. Mid‐Cenozoic exhumation affected the eastern North Sea Basin and the onset of this event correlates with a latest Oligocene unconformity (ca. 24 Ma), which indicates a major Scandinavian uplift phase. The deeper burial that caused the late Oligocene thermal event recognized in the AFTA data reflect progradation of lower Oligocene wedges derived from the uplifting Scandinavian landmass. The onset of Scandinavian uplift is represented by an earliest Oligocene unconformity (ca. 33 Ma). Late Neogene exhumation affected the eastern (and western) North Sea Basin including Scandinavia. The sedimentation pattern in the central North Sea Basin shows that this phase began in the early Pliocene (ca. 4 Ma), in good agreement with the AFTA data. These three phases of Cenozoic uplift of Scandinavia also affected the NE Atlantic margin, whereas an intra‐Miocene unconformity (ca. 15 Ma) on the NE Atlantic margin reflects tectonic movements of only minor amplitude in that area. The study demonstrates that only by considering episodic exhumation as an inherent aspect of the sedimentary record can the tectonic evolution be accurately reconstructed.

The CentralGrabenarea wasfilled withathick pileofsediments duringthe MiddleM ioceneQuaternary,correspondingto aperiodof15Ma.Ashydrocarbon expulsion from the most prolific source rock, the UpperJurassic BoMember,wasinitiated only 20 Ma BP andstill occurs today,the MiddleM ioceneQuaternary evolution isimportant.Int he MiddleMiocene, the CentralGrabenarea wascovered byasea with waterdepthof500 -700 m. Duringthe LateMiocene(Tortonian),the basinwassuccessively filled byprograding slopeanddeltaic sedimentsfrom the northeast. The progradationalinfill resulted inlocaltiltingofthe substratum dueto the loadinge ffecto fthe deposits. Int he latest LateM iocene(Messinian),the maininput ofsediments occurred from the south, asillustrated byathick onlappingsuccession ofupperMessiniansediments. Pliocene sedimentation wascharacterized byr egularinfill from the east withinashelfto shallow marined epositional environment.Followingthe Miocenea ndP liocene, the NorthS ea Basint ilted dueto stronguplifto fthe Fennoscandians hielda ndi ncreased subsidence andsedimentation ratesw ithint he CentralGrabenarea.This furthercomplicated the maturation ofthe source rock, migration pathways anda ccumulation ofh ydrocarbons. The consequence ofthiscomplexburialhistory isexemplified bythe Kraka andHalfdanfields. The Kraka Field hasalarge down-flankoilaccumulation,which ist he result ofaporosity anomaly resultingf rom anearly invasion ofoilint hisp osition beforethe latetiltingofthe NorthS ea Basin. The history ofthe non-structural accumulation ofthe HalfdanFieldcanbe readily modelled;itconstituted asimplefour-waydipclosureduring the LateMiocenewhenpeak oilmigration occurred.The Quaternary tiltingofthe NorthSea Basindueto upliftof the FennoscandianShielda ndstrongsubsidence ofthe CentralGrabenarea resulted inad istinctgradient favouringlong-distance migration ofhydrocarbons. The occurrence ofviablemigration routes,especially within Paleocenesandlayers,hasresulted inlong-distance migration ofoilinto the Sirisubmarinevalleysystem. The most northern indication ofh ydrocarbons hasbeenr ecognized asfaras7 5kmfrom the source area.Longdistance migration ofh ydrocarbons isalso indicated bydirecthydrocarbon indications( DHIs) throughoutt he Cenozoic succession int he DanishN orthS ea.DHIsareparticularly prominent abovek nown hydrocarbon accumulationsint he CentralGraben. Thisindicatesp ronounced verticalm igration,f or instance alonga ctive faults,abovethesestructures.

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Basin modelling and compaction studies based on sonic data from the Mesozoic succession in 68 Danish wells were used to estimate the amount of section missing due to late Cenozoic erosion. The missing section increases gradually towards the coasts of Norway and Sweden from zero in the North Sea to c. 500 m in most of the Danish Basin, but over a narrow zone it reaches c. 1000 m on the Skagerrak-Kattegat Platform in northernmost Denmark. The increasing amount of erosion matches the increase in the hiatus at the base of the Quaternary, where Neogene and older strata are truncated, and the Mesozoic succession is thus found to have been more deeply buried by c. 500 Paleocene-Miocene sediments in large parts of the area. These observations suggest that the onset of erosion occurred during the Neogene, and that the Skagerrak-Kattegat Platform was affected by tectonic movements prior to glacial erosion. In southern Sweden just east of the Kattegat, the exposed basement of the South Swedish Dome attains altitudes of almost 400 m. The formation of the Dome started in the Late Palaeozoic, but geomorphological investigations have led to the conclusion that a rise of the Dome occurred during the Cenozoic. We find that the pattern of late Cenozoic erosion in Denmark agrees with a Neogene uplift of the South Swedish Dome and of the Southern Scandes in Norway. This suggestion is consistent with major shifts in sediment transport directions during the late Cenozoic observed in the eastern North Sea, and with formation of a new erosion surface as well as re-exposure of sub-Cambrian and sub-Cretaceous surfaces in southern Sweden. The Neogene uplift and erosion of southern Scandinavia appears to have been initiated in two phases, an early phase of ?Miocene age and a better-constrained later phase that began in the Pliocene. Neogene uplift of the South Swedish Dome with adjoining areas in Denmark fits into a pattern of late Cenozoic vertical movements around the North Atlantic.