A synthesis of tectonically-related stratigraphy in the North Atlantic-Arctic region from Aalenian to Cenomanian time

VIDAR BERGO LARSEN

Larsen, V. B.: A synthesis of tectonically-related stratigraphy in the North Atlantic-Arctic region from Aalenian to Cenomanian time. Norsk Geologisk Tidsskrift, Vol. 67, pp. 281-293. Oslo 1987. ISSN 0029- 196X.

The stratigraphic evolution in the North Atlantic-Arctic region from Aalenian (187 Ma) to Cenomanian (97 Ma) time is described in relation to four tectonic phases. Thefirst two are related to the failed attempt of the opening of the North Atlantic in Jurassic time. Rift basins formed as a response to extensional forces associated with a clockwise rotation of the North American (Laurentian)/Greenland plate and a clockwise rotation of the African plate during the opening of the Tethys. Regional uplift is suggested north of the northward migrating pivot point in the North Atlantic, with responding diachronous development of fan delta sedimentation. The last two phases are related to the slightly anticlockwise rotation of the Greenland plate giving rise to compressional tectonics and uplift along many basins within the region in Neocomian time (Phase III), while extensional tectonics dominated when further rotation and northwest migration of the Greenland plate proceeded in Aptian-Albian time (Phase IV). The stratigraphic evolution within the individual basins ftanking the North Atlantic and the Norwegian­ Greenland Sea is to a certain degree different, but nevertheless reftects the paleopositions of the basins within the plate tectonic framework through time. One basin may reftect compression and uplift in the same time span (Tectonic Phase) as another basin may be within an extensional regime,i.e. Haltenbanken vs. Faeroe Basin (Fig. 2). These differences fingerprint the tectonic evolution, and it is the idea of this synthesis that the stratigraphic evolution of the individual basins as well as their differences follow a certain pattem and is suggested to be govemed by an overall plate tectonic model for the North Atlantic within the Aalenian-Cenomanian time span.

V. B. Larsen, Statoil, Postboks 1212, N-5001 Bergen, Norway.

The sedimentary basins along the borderlands of An understanding of the dynamic evolution in the North Atlantic and the Norwegian-Greenland the interrelationship between regional stratigra­ Sea as well as within the Barents Sea are, and will phy and tectonics (or tectonic history) may make continue to be, sites of extensive exploration for it possible to use data from the hetter known oil and gas. At present there is a considerable basins for predicting the stratigraphic evolution amount of data on seismic, borehole and outcrop in undrilled areas. The result should be a hetter descriptions available to the oil industry. In this understanding of the petroleum potential in paper, borehole information from Nova Scotia, untested areas along the borderlands of the North the Grand Banks and New Foundland basin in Atlantic and the Norwegian-Greenland Sea, as the southwest, onshore data from East Green­ well as within the Barents Sea. land, the Sverdrup Basin and Spitsbergen, seismic The model described here for the evolution of and well-data from the Barents Sea, Troms l, the North Atlantic and the Norwegian-Greenland Haltenbanken and southwards to the Viking Gra­ Sea from Aalenian (187 Ma) to Cenomanian ben and West Shetland have been used to syn­ (97 Ma) time should be regarded as a working thesize the stratigraphic and tectonic evolution hypothesis which will be subject to modifications into a plate tectonic model. It is suggested here as new information becomes available. This paper that the stratigraphic evolution of the individual is a review of previously published data integrated basins may reflect the overall plate tectonic with new basic data and interpretations based on evolution. Statoil's extensive exploration activity in the area. 282 V. B. Larsen NORSK GEOLOGISK TIDSSKRIFf 67 (1987)

Fig. l illustrates the observed stratigraphy in In Middle Jurassic time sea-fioor spreading the individual basins, and in the following an started at the intersection between the east-west attempt is made to relate and integrate this into Tethys-Central Atlantic rift/wrench zone and the a plate tectonic model for the North Atlantic from north-south North Atlantic Rift system. The Bathonian to Cenomanian time. Figs. 2, 9, 11 and spreading axis at this time extended from the 20 illustrate the paleogeographic development Azores Transform Fracture Zone in the north to superimposed on the regional tectonic evolution the Equatorial Transform Fracture Zone in the within the discussed time frame. The southeastern south (Pitman & Talwani 1972). part of the maps are partly taken from Ziegler During the early Middle Jurassic (Toarcian­ (1982). Bathonian), Ziegler's 'Main Kimmerian Tectonic Phase' caused considerable paleogeographic Pre-mid-Jurassic framework changes in the Northwest European Basins (Ziegler 1982). This tectonic episode, charac­ The Caledonian, Devonian and Carboniferous terized by volcanic activity and uplift, may have structural evolution bad a significant effect on the been caused by thermal dorning related to the history of Permian and younger basin evolution onset of sea-fioor spreading in the Central along the North Atlantic Borderland. The Permo­ Atlantic. Uplifted areas (the Central North Sea Mesozoic and Cenozoic rifting, wrenching and rift dome (Ziegler 1982)) served as provenance spreading are mostly controlled by reactivation for the regressive Middle Jurassic Brent deltaic of zones of crustal weakness established prior to sandstone which prograded over much of the Permian time. The Caledonian suture zone forms North Sea at that time. sinusoidal lineations along a northeast-southwest The partial or even total interruption of the trend (Johnson & Dingwall 1981), and probably connections between the Tethys and the Arctic has a bearing on the Mesozoic-Cenozoic opening seas in early Bajocian time may be related to this of the North Atlantic and the Norwegian-Green­ doming, indicating that doming may also have land Sea, as well as the configuration of the tec­ taken place in the area between West Shetland tonic stress pattern in a pre-opening context. and South East Greenland. Bukovics et al. (1984) recognized a presumed intra-Permian refiector on the Trøndelag Plat­ form. This probably represents Upper Permian carbonates equivalent to the Upper Permian Late Middle Jurassic uplift/rifting limestone in East Greenland (Surlyk et al. 1984). and clockwise rotation of the North On both Haltenbanken and East Greenland, mid­ American/Greenland plate Permian block faulting seems to have occurred (Phase I) prior to the deposition of these limestones. On Svalbard Carboniferous sediments seem to As sea-fioor spreading continued in the Central be arranged en echelon in basins between Bille­ Atlantic, the North American/Greenland plate is fjorden and Palea-Hornsund Lineaments. Trans­ here suggested to rotate clockwise relative to the current movements along northwest-southeast Eurasian plate. Two different structural regimes and east-west trends during the Carboniferous affected sedimentation. To the south, a north­ and Permian may have taken place from the wards propagating regime was accompanied by Agadir Fault Zone in North Africa to the subsidence and northward migration of open mar­ Hornsund Fault Zone in Spitsbergen. These ine sands and shales. To the north, between lineaments may refiect horst and graben con­ Greenland and Mid-Norway, plate rotation figurations overlain by marine Upper Permian created a local E-W compressional regime which carbonates and evaporites. They may also rep­ resulted in uplift and N-S prograding fan delta resent precursors for the Tertiary fracture zones sequences (Fig. 2). As extension and opening associated with the opening of the North Atlantic proceeded northward, this compressional regime and the Norwegian-Greenland Sea. Late Permian also rnigrated northward, and the sequence of fan­ time represents a relatively stable tectonic period delta sediments followed by marine transgressive in the area. Possible rift associated sediments sands became younger northward. The effects of occur in the Triassic succession (Jacobsen & Van this tectonic pattern, although modified by local Veen 1984). faulting, can be seen throughout the North NORSK GEOLOGISK TIDSSKRIFT 67 (1987) TSGS Symposium 1986 283

Atlantic (e.g. Pelion Member, East Greenland, The Grand Banks area received carbonate and Upper Tomma Formation, Haltenbanken). deposition during Bajocian time and alternating siliciclastics and limestones from Bathonian to Kimmeridgian time (Fig. 5) (Wade 1981). On the Northern North Sea and Møre Basin Scotian Shelf, carbonate deposition was initiated After the northward progradation of the Brent during the Bathonian transgression. These delta system (Broom, Rannoch, Etive and Ness Bathonian carbonate banks, resting on Bajocian Formations, (Fig. 1)), the transgressive Tarbert clastics, were drawned during the Callovian trans­ Formation was added to the system in Bathonian­ gression, while the East Newfoundland Basin still Callovian time. Well control shows that the north­ received sand. In these aæas Phase I tectonics em limit of the Brent delta-front can be drawn at bad already reached a more mature stage with approximately 61°31' north. The water further to the formation of oceanic crust seawards of the the north was too deep for a delta system to be Scotian Shelf. maintained (Fig. 3), although turbidite sequences The time of break-up of the Scotian Shelf/ may be expected. Wells drilled north of 61°30' Essaouira-Souss conjugates was approximately show Bajocian-Bathonian shale sequences, sup­ 180 Ma; for the Grand Banks/Iberia conjugates porting the northern limitation of the delta sys­ 115 Ma; and for the Grand Banks/Rockall 90 Ma tem. (McWhae 1981). This 'deep water' environment extended The Arga Salt (Fig. 5) is older in the East throughout Bathonian time from the Møre Basin Newfoundland Basin and younger on the Scotian in the northeast to the Rockall Trough in the Shelf, thus refiecting the southward transgression southeast. This area had already deepened in of an arm of the Tethys across the now subsided Bajocian time, as shown by the northward ter­ Triassic basins. Break-up, on the other hand, mination of the Brent Group (Fig. 4), and prob­ becomes younger northward, refiecting south to ably deepened further during the Bajocian­ north opening of the North Atlantic. Bathonian transgression of the Tarbert Forma­ tion. The transgression is probably the result of a East Green/and - Mid Norway tectonic event (e.g. an increased spreading rate in the Central Atlantic) at this stage (Phase I) in The East Greenland Basins are bounded to the combination with a global sea-level rise. Sim­ east and west by north-south striking faults, which ultaneous tilting of fault blocks, angular uncon­ are cut by northwest-southeast faults. This fault formities and regressive sequences along the basin pattern creates a series of diamond-shaped fault margins (Kross Formation, Troll Field) support blocks which subsided progressively from south this model (Fig. 4). to north. This subsidence pattern may be Further south in the northern North Sea (Fig. 4) explained by a gradual re lease of east-west strain the regressive sequence kept pace with the trans­ by a clockwise rotation of the Greenland-North gression until Callovian time (Hugin Formation), American plate and a continued opening of the indicating that the Viking Graben bad a regional rift basin from southwest to northeast in the North plunge to the north. The Viking Graben was, in Atlantic. Sinistral transpressive strike-slip faults the later part of Middle Jurassic time, a southward in Trolle Land (northwest-southeast) in North­ extending arm of the Møre-Rockall rift basin east Greenland (Håkansson & Pedersen 1982) which again became more developed further and in the western Barents Sea may be related to south. this rotation. The progressive subsidence of rift basins north­ ward is the opposite of what was the case in the Southwest Margin Permo-Triassic when the sea transgressed south­ South of the Newfoundland-Azores-Gibraltar westwards from the Barents Sea. The high fracture zone (the proto-oceanic gulf), sedi­ area north of Kong Oscar's Fjord (Fig. 2) limited mentation of carbonates and marine clastics took further northward extension of the Lower Jurassic place in a shelf setting. Middle Jurassic dolerite Kap Stewart Formation and Neill Klinter For­ dike swarms which can be related to extensional mation. The Middle Jurassic Vardekløft For­ tectonics have been mapped in southwest Green­ mation (Birkelund & Perch-Nielsen 1976), land (Watt 1969). however, was deposited both on Jameson Land 284 V. B. Larsen NORSK GEOLOGISK TIDSSKRIFr 67 (1987) and on Traill Ø. The Traill Ø-block was then ern part was transgressed in Middle Bathonian downfaulted along the Kong Oscar's Fjord and time. Kejser Franz Joseph's Fjord to the same level as During deposition of the Pelion Member on the Jameson Land area (Surlyk 1978). Continuous East Greenland it is suggested that continuous movements had also occurred along the north­ (accelerated?) clockwise rotation of the Lau­ south striking boundary faults. rentian plate resulted in compression and uplift Middle Jurassic fault-controlled subsidence in the area between north of Hochstetter Foreland also occurred on Wollaston Foreland. The area and Vestfjord Basin (Fig. 2) on the Norwegian between these basins, from Kejser Franz Joseph's side. This area may have acted as a provenance for Fjord to Godthaab Fjord, acted as a barrier and distribution of clastic material toward the south in may be regarded as a continuation of the Liver­ the northern bays of the North Atlantic (Fig. 2). pool Land Foreland. Fan delta sediments in the uppermost part of The break in sedimentation on East Greenland the Tomma Formation in the Haltenbanken area (hiatus from Late Toarcian to Late Bajocian time) are suggested to have prograded towards the prior to the deposition of Vardekløft Formation southeast (Aasheim & Larsen 1984). The sedi­ suggests that this area was in a more proximal mentation occurred contemporaneously with the position on the rift margin during the subsequent Pelion Member and the northern east-west com­ transgression than Mid-Norway (Haltenbanken) pression (Figs. 6, 7). Periods of non-deposition and the northern North Sea, which received con­ (Bathonian-Oxfordian time) on Andøya, the tinuous deltaic sediments into Bajocian time north-south synforms created here (Dalland, ( denudation of the relief created by the 'Mid pers. comm.), as well as subaerial exposures of Kimmerian' tectonic phase). An Aalenian-Bajo­ basement in the area may support this model. cian delta system should therefore be expected The transgressive nature of the Vardekløft For­ on the East Greenland Shelf (Upper Neill Klinter mation is clearly demonstrated by comparing the Formation). thicknesses of the Pelion Member and the onlap­ The Late Bajocian transgression and eustatic ping Fossilbjerget Member. These are lOm and sea level rise in the western European Basins, 510 m thick respectively in the south and 600 m which is suggested to be related to the onset versus 120 m in the northern area (Heinberg & of the creation of oceanic crust in the Central Birkelund 1984). To the north, a renewed regres­ Atlantic, caused transgression in the East Green­ sive sequence is seen in the sandy Olympen For­ land Basin (base Vardekløft Formation; Sorte mation (Callovian-Oxfordian time), indicating a Hat Member (Fig. l)) and in the Haltenbanken potentially more or less continuous sand depo­ area (shaly middle part of the Tomma Form­ sition in the northern part of the bay area from ation). Late Bajocian to Oxfordian time (Fig. 9). Several This transgression enabled mud sedimentation undrilled sub-basins within the North Atlantic to begin somewhat earlier in the main rift basin area may contain similar sandy sequences. (Mid Norway-East Greenland-Rockall) (Middle Examples are Vestfjord Basin, Træna Basin, Bajocian) than in the northern North Sea (Early inner Vøring Basin and the deeper unnamed Bathonian), again indicating that the secondary basins situated between the Nordland High and rift (Viking Graben) had a plunge towards the the Kejser Franz Joseph's Fjord in East Green­ northwest. On East Greenland the trough-shaped land (Fig. 6). basins were well suited to accumulate coarse In conclusion, the chances are good that these clastics from the river systems draining along the basins contain thick reservoir sandstones devel­ zones of weakness within the basement (north­ oped in response to the Phase I tectonism. This south, northwest-southeast). In spite of the retlects the area's proximity to the change from strong transgression, the resulting depositional the southern extensional rifting to the northern sequence has a coarsening upward character compressional uplift. The sub-basins may tend to (Sorte Hat Member-Pelion Member (Fig. 1)). be relatively narrow and trough-shaped, repre­ As the sea advanced from south to north, the senting ideal locations for deposition of coarse Pelion sandstone Member in the East Greenland clastics from the provenance area ·and thereby Basin was overlain by the shaly Fossilbjerget keeping pace with the transgression. Thus Member (Fig. l) in the southern part of Jameson coarsening upward sequences can be developed Land from Early Bathonian time, while the north- in spite of the transgression (Fig. 7). NORSK GEOLOGISK TIDSSKRIFT 67 (1987) TSGS Symposium 1986 285

As a consequence of this geological setting, the The Late Jurassic rifting. area between Møre and South-East Greenland Callovian - Early Kimmeridgian should have bad deposition of relatively deep marine shales during the Middle Jurassic time. (Phase Il) However, near the coast and within fault­ Rifting in many of the basins bordering the North bounded half-grabens within some of the fjords Atlantic as well as the opening of the Arctic in the Møre-Trøndelag area, shallow marine sand Seaway was a result of continuous sea-ftoor or even alluvial sand may be expected. spreading south of the Newfoundland-Azores­ Gibraltar fracture zone (Laughton et al. 1975) as Northeast Greenland-Svalbard-Barents the Tethys prograded westward into the 'Gulf of Shelf Mexico'. Rift-associated sediments of Late Jur­ assic age are commonly found within the North The Late Bajocian/Bathonian transgression of Atlantic basins. Phase I did not reach the area of maximum com­ pression, and sand sedimentation was therefore West Britain - North Sea - Southwest continuous into the Troms area (Stø Formation) Margin- East Green/and - Mid Norway (Figs. l, 2, 6) (Olaussen et al. 1984). The Svalbard area became emergent possibly IntensifiedLate Jurassic regional extension across due to the sinistral transpression along the Trolle the Arctic-North Atlantic rift system was Land Fault Zone on northeast Greenland, and accompanied by northwest-southeast wrench possible fault activity along the Billefjord­ faults in the North Sea area. In the Viking Graben Lomfjord fault system. (cf. Brentskardhaugen and the Moray Firth Basin, crustal extension led Beds). Franz Joseph's Land at that time was to progressive subsidence of rotational fault partly emergent, while the Novaya Zemlya and blocks. Timan-Pechora Basins were dominated by fresh­ Ziegler (1982) suggested that the Rockall­ water sandstones with an abundance of plants Færoe Rift Zone gradually became updomed dur­ and rootlets (Kelly 1985). No deposits of Middle ing the Late Jurassic. It is suggested here that this Jurassic age are found onshore in northeast doming is more related to Phase Ill (Neocomian) Greenland (Håkansson & Stemmerik 1984). On than to Phase IL In the Callovian-Early Kim­ Spitsbergen, however, the phosphoritic and meridgian time, a rift basin existed extending quartzitic conglomerate (Brentskardhaugen from the Rockall Trough northeastward to the Beds) of Late Bajocian-Early Bathonian age may southwest Barents Sea. This implies that the be related to Phase I sinistral transpression. The Greenland-North American plate was still rotat­ phosphoritic nodules contain remanie faunas of ing clockwise, causing continued tensional move­ Toarcian?-Bajocian age, indicating that sedi­ ments along the rift margins. ments of this age had been deposited prior to the Left lateral movements along the Great GJen erosion (Steel & Worsley 1984). and Midland Valley Fault systems are in accord­ The regression character of the Lower Jurassic ance with this and can explain the cumulative Wilhelmøya Formation on East Svalbard, with opening to the northwest of the wedge-shaped westerly transportation, is here suggested to be Viking Graben (Threlfall 1981). related to crustal doming east of Kong Karl's Pegrum et al. (1973) suggested that a transverse Land (Fig. 8). 'barrier' of thickened crust, caused by the com­ The penecontemporaneously deposited phos­ bined Caledonian and Hercynian orogenic beits, phoritic conglomerates in western Spitsbergen crossing the Proto-Atlantic delayed the north­ indicate that a seaway existed between the ward extension of the Atlantic opening, and eastern dome area and the compressionally up­ accounted for the complex history of the opening lifted area between northeast Greenland and of the area directly north of the Newfoundland­ north Norway. This seaway was probably elon­ Azores-Gibraltar Fracture Zone. Extension at gated northwest-southeast and is thought to have that time occurs across areas of former uplift and widened towards the northwest, where marine compression, and the area as far north as Western muds and shelf sands are found in the Sverdrup Approaches, Celtic Sea, Porcupine Seabight, and Basin (McConnel Island Formation and Hiccles Rockall is dominated by the formation of Cove Formation), (Embry 1984) (Fig. 2). numerous half-grabens. These features may rep- 286 V. B. Larsen NORSK GEOLOGISK TIDSSKRIFr 67 (1987) resent successive attempts of the spreading ridge major highs as a response to the latest tectonic to breach the mentioned barrier (Pegrum & event of Phase Il, and will be equivalent to the Mounteney 1978). Hareelv Formation on the Greenland side or the The rapid northward transgression related to basal part of the Brae/Magnus Formations in the this period of rift-faulting and subsidence gave British North Sea (Fig. 9). rise to resedimentation of sandstones along the basin margins (Fig. 9). As is often the case in half­ Barents Shelf- Svalbard - Northeast grabens, the steep sides developed turbidites and Green/and submarine fans, whereas on the more gentle slopes, vertical aggregation of regressive shallow The doming suggested here in the northeast marine sands went on during overall transgressive Barents Sea, which could have caused the pro­ events. The flanks of subaerially exposed and gradation of the Wilhelmøya Formation, col­ eroded fault blocks are often fringed by shallow lapsed in Late Middle Jurassic time. A north marine sandstones reworked from older Middle northeast-south southwest failed rift arm may Jurassic deltaic sands. have formed from the Arctic Basin toward the As described earlier, Pliase I associated sand­ culrnination between Hopen High and the Sen­ stones on East Greenland continued to be tralbanken High (Fig. 9). deposited into Oxfordian time in trough-shaped The Svalbard area was transgressed in Cal­ sub-basins (Olympen Formation). This area did lovian time and the open marine shales of the not receive sandstone sequences related to Phase Janusfjellet Formation were deposited. Marked Il until the eastern high structure subsided below thickness vanatwns are seen across the sea leve!, creating a more open marine environ­ Agardhbukta and Billefjord lineaments sug­ ment and exposing sediments to marine rework­ gesting penecontemporaneous movements of ing from waves and longshore currents (Aldinger these fault systems during the transgression and Elv Formation) (Fiirsich & Heinberg 1983). the associated parallel eastem rifting. Basic On the Norwegian Shelf area, between 60 and intrusions associated with these fault movements 62°N, Phase Il associated sandstones began to support a model of extensional tectonics (Harland develop already in Callovian time. This area con­ et al. 1974). tains a large volume of Triassic and Jurassic sand­ Because of the increased relief and subsidence, stones, which were exposed to reworking as a the northeast coast of Greenland received near­ result of gentle westward tilting during the for­ shore marine to limnic deposition in the Lade­ mation of the north Viking half-graben. Thus, gaardsaaen Formation (Håkansson & Stemmerik the area received shallow marine sands during 1984) from Mid Oxfordian time. This formation Callovian (Fensfjord Formation) as well as Oxfor­ is tectono-stratigraphically the equivalent to the dian-Kimmeridgian time (Sognefjord Formation) Upper Jurassic sandstones in the Troll area (Hellem et al. 1986). between 60° and 61°N on the Norwegian shelf. Due to the northward migrating pivot point, a On the opposite side of the rift system, Franz delay in the start of open shallow marine depo­ Josephs Land received deposition of marine aren­ sition is to be expected northwards along the aceous limestones over clays and siltstones associ­ Norwegian coast. A turbiditic or restricted fan ated with basic intrusives (Fig. 10). In the Novaya delta sedimentation with a broad northwest­ Zemlya area, marine bituminous limestones were southeast to northeast-southwest alignment could deposited during this phase, while the Pechora be the case for Bathonian-Callovian and Lower Basin was transgressed in Callovian time, and Oxfordian sedimentation north of 62°N. The fre­ a major seaway reached south to the Tethys quency of sand deposition is likely to increase (Fig. 9) (Kelly 1985). northward towards the embayment of the North Atlantic Sea (Fig. 9). An Oxfordian-Kimmeridgian development of Latest Jurassic and Neocomian an open, shallow marine longshore sandstone transpression and uplift (Phase Ill) sequence is expected locally near the Norwegian coast as well as along local subaerial highs ( frin­ After the Late Jurassic rifting episode, which ging sands). Oxfordian-Kimmeridgian turbidites created a new set of aborted rift basins with and submarine fan deltas may be found west of different orientations along the North-Atlantic NORSK GEOLOGISK TIDSSKRIFT 67 (1987) TSGS Symposium 1986 287

. borderlands, there seems to be a concentration Member (Umpleby 1979). They become finer of the tectonic trends in a northeast-southwest grained and slightly more deltaic to the southeast direction. The gradual closure of the Tethys Sea and interfinger with the deltaic sandstones of the and the onset of sea-floor spreading between the Missisauga Formation of the East Newfoundland Azores and Charlie Gibbs Fracture zones (Ziegler Basin, Grand Banks and Scotian Shelf (Figs. 11 1982) brought about tectonic changes in the cen­ and 18). tral part of the North Atlantic rift system. Prior The creation of a northwest-southeast aula­ to the Cretaceous rifting (Phase IV) there was a cogen toward the BaffinBay area indicates exten­ period of uplift along a northeast strike (Fig. 11). sional forces associated with movements of the Greenland plate towards the northeast. This is in accordance with the dextral transpression in the West Shetlands northeast Atlantic described in this paper. Evidence for Phase Ill upliftin West Shetlands is summarized below (Fig. 12): Northern North Sea l. The British Isles were more subaerially exposed in Neocomian time than during the The Tampen Spur and other 'structural highs' in early Late Jurassic. the northern North Sea went through con­ 2. The transport direction of Neocomian shallow siderable erosion leading to peneplanation and marine sandstones is toward the southeast on subsequent capping by Barremian limestones in the western edge of the West Shetland Basin spite of the late Ryazanian (Berriasian) trans­ (Fig. 12). gression (Rawson & Riley 1982). The structures 3. Cretaceous turbidite deposition into the West seem to have been tilted to the southeast with a Shetland and Færø Basins started in the post Oxfordian-pre-Barremian onlap from the Albian. An unconformity is seen between southeast (Fig. 13). This is in accordance with a the Barremian limestone and the Albian change of the structural style in this area during sequences. the Phase Ill time span. A north-south riftsystem 4. Active faulting and submarine fan delta with extensional tectonics (Phase Il) changes in to deposits are pre- and post-Neocomian respect­ a northeast transpressional system with dextral ively along the West Shetland Basin. displacement of the north-south rift faults. Associated with this is the formation of reverse faulting and northeast-striking synforms which are onlapped by pre-Barremian clastics in the West Green/and - Labrador Shelf- Baffin north west. Bay- Grand Banks The change in the tectonic regime in the North During Phase Ill, and partly in Phase IV, the Atlantic area is suggested to have initiated a Canadian Arctic Islands, Baffin Bay and Lab­ change in bathymetry, giving rise to reduced rador Sea were largely in a non-marine setting. water circulation. The previously open north­ The persistence in continental conditions in­ south Oxfordian 'shale basin' may, by the dextral creases towards the northwest. The sediments northeast-southwest transpression, have created on the Labrador Shelf and Bylot Island Iie in a submarine barriers which reduced the water cir­ fault-bounded graben, while in West Greenland culation and formed anoxic sub-basins. This, the basin contains faults which parallel the axial superimposed on the regional uplift in the North spreading center of Labrador-Baffin Bay (Sri­ Atlantic, may have some bearing on the expla­ vastava et al. 1981). nation of the development of the anoxic Draupne The oldest Mesozoic rocks penetrated by drill­ Formation (Fig. 11). ing on the Labrador Shelf are weathered subaerial Pre-Barremian-post -Oxfordian shallow marine basaltic lava flows, aquagene tuffs, and minor sandstones found in the northern North Sea are sediments giving ages between Berriasian and thought to be related to this northeast-southwest Hauterivian (Alexis Formation) (Fig. 17). Within dextral transpressional tectonic phase and are the northwest-southeast trending aulacogen, the expected on a regional scale to be elongated basalts are overlain by coarse arkosic sands, coals northeastwards along the exposed structures at and shales of the Bjarni Formation and Snorri that time. 288 V. B. Larsen NORSK GEOLOGISK TIDSSKRIFT 67 (1987)

The sandstones interfinger with the Kim­ East Green/and meridge Clay Formation, indicating that the latter is not necessarily everywhere a deep marine shale. After culmination of the deposition of deep mar­ Deeper marine sandstones, such as the upper ine sand associated with extensional block faulting part of the Magnus and Brae Formations, are in the Upper Jurassic (Hareelv Formation), a believed to be related to the same tectonic phase, marked change in the tectonic and deposition but these sands were deposited downflankof high style occurred in the Neocomian within the fault scarps or more distally from an exposed southern Jameson Land area. The relatively deep high. marine Hareelv Formation ( containing sedi­ mentary dikes and gravity flows) is overlain by the shallow marine Raukelv Formation. Within Mid Norway- Møre- Haltenbanken the Kap Leslie Formation in Milne Land a Kim­ Although far fewer wells have been drilled in this meridgian oil shale is developed (Gråkløft area than in the North Sea, a similar trend can be Member). This oil shale is associated with the observed here. The north-south Late Jurassic rift above-mentioned change from the deep marine faults are superimposed by northeast-southwest (the tectonically active Hareelv Formation) into dextral wrenching of Neocomian age. The base­ shallow marine conditions (Raukelv Formation), ment was exposed on the Nordland Ridge during (Surlyk et al. 1973), (see Fig. 15). this time, as was the Rona Ridge in the West It is suggested that this 'hot-shale' was Shetlands Basin. The north northeast-south deposited under anoxic conditions during a sub­ southwest fault trends, the Kristiansund-Bodø aerial exposure of the area southeast of J ameson Fault Complex, as well as the Bodø High, the Land. The younger Salix Dal Member shale, situ­ Frøya High, and the Nordland Ridge, etc. ated between the two shallow marine sandstone (Gabrielsen & Robinson 1984), all give evidence members, Sjælland and Fynselv, of the Rauk elv of a more pronounced northeast-southwest tec­ Formation, thins toward the southeast. An uplift tonic grain than was the case in the northern in the southeast may have caused this thinning as North Sea, and are more similar to the West well as deposition of shallow marine sandstones Shetland area. (Raukelv Formation) in the southern part of The northward increase in the rate of Early Jameson Land. Cretaceous dextral transpression in the North Sea The shallowing from Hareelv Formation to and the dominant northeast-southwest tectonic Raukelv Formati on is in accordance with the pro­ lineament both in Haltenbanken, Møre and the posed plate-tectonic model for the Neocomian, West Shetlands, indicate a regional northeast­ Phase Ill, with a transition from clockwise to southwest tectonic regime centred along a line anticlockwise rotation of the Greenland plate fromRockall Trough to the Bear Isle Basin. This relative to northwest Europe. The anticlockwise is suggested here to be due to the relative move­ rotation, associated with the opening of the Lab­ ments between Greenland and northwest Europe. rador Sea, gave rise to doming, reverse faulting As for the West Shetlands and northern North and subaerial exposure of fault blocks from the Sea, the tectonic inversion along the strike gave West Shetlands in the southwest to the Sen­ rise to erosion and the formation of Neocomian tralbanken High in the northeast within an area sandstones along the southeastern margin of the of dextral transpression. exposed highs (Fig. 14). The inversion is thought The west-southwesterly tilted fault blocks of to have started in the Kimmeridgian, and shallow Valanginian-Volgian age in the Wollaston For­ marine sandstones (Frøya Formation) are inter­ land area may be regarded as an extension area bedded with the organic rich Nesna Formation on within the suggested northeast-southwest dextral Haltenbanken (Fig. 1). transpression southeast of Jameson Land during Reservoirs of this kind can be expected within the anticlockwise rotation of the Greenland plate. many of the small basins bordered by pre­ Within this tectonic pattern during Phase Ill, Barremian-post-Oxfordian exposed highs along shallow marine sandstones (Raukelv Formation) the northeast-southwest trend. The northwest­ were deposited along the transpression zone, erly onlap of Neocomian strata supports the con­ while submarine fan deposits (Lindemansbugt cept of an Earl y Cretaceous uplift along this trend Formation) (Surlyk 1977) were deposited within (Figs. 14 and 15). the extension area. This extension/compression NORSK GEOLOGISK TIDSSKRIFT 67 (1987) TSGS Symposium 1986 289 relationship is also expressed along the 'dog leg' Sea. This change from dextral transpression in fault pattern within the Haltenbanken area. the area from West-Shetland to Sentralbanken High to dextral transtension in the area between Spitsbergen and Franz Josephs Land is suggested Northeast Green/and, Svalbard and Barents here to be due to the slight rotation anticlockwise Sea of the Greenland plate (Fig. 11). Fault movements along northwest-southeast Stratigraphically this is supported by rift associ­ trends, fromNortheast Greenland and the South­ ated stratigraphy in Svalbard and Wandel Sea west Barents Sea, seem to alternate between Basin which is time equivalent to the shallowing dextral and sinistral through time. of basins further south in the North Atlantic The Ladegaardsaaen Formation on Northeast (Fig. 1). Greenland (Mid Oxfordian-Early Cretaceous) The sandstones associated with this tectonic overlies Paleozoic-Triassic rocks with angular event built up the Slettnes Formation in the Troms unconformity. This is interpreted by Håkansson area and the Awingak Formation in Sverdrup & Pedersen (1982) to be related to ?Early Jurassic Basin (Embry 1985a), Ladegaardsaaen For­ sinistral transpression along a northwest-south­ mation on northeast Greenland, and local fringing east strike (ref. Phase I and Fig. 16). sands along fault scarps on Spitsbergen. However, There is no evidence of tectonic activity on uplift Phase Ill associated sandstones equivalent northeast Greenland during Neocomian time. to those on East Greenland and Haltenbanken, The next phase of tectonic activity along the can be expected in the Hammerfest Basin and in Trolle Land Fault Zone is thought to have the area between the Sentralbank High and the occurred in Late Cretaceous when rapid accumu­ Nordkapp Basin. lation of immature sediments took place in pull­ The shaly deposits within the area of extension apart basins trending northwest-southeast (Phase (the continuation of the Late Jurassic rifting IV). Dextral strike-slip with en echelon domal stage) in the northeast Barents Sea form excellent folds are disturbing the pull-apart basins during a cap rocks above the blockfaulted Late Triassic­ transpressional phase in Upper Cretaceous-Pale­ Early Jurassic sandstones. Hydrocarbons in these ocene time (Håkansson & Pedersen 1982). sands may have been sourced from the bituminous The Neocomian on Spitsbergen is characterized Triassic Botne heia Formation which probably has by the shale deposits of the Rurikfjellet Member reached the oil window along the suggested rift (Fig. 1). Differentialmovements have been docu­ system (Fig. 10). This rift system is probably mented along the north-south Lomfjorden­ formed from the northern edge of the Barents Agardhbukta and Billefjorden lineaments around Shelf between Kong Karls Land and Franz the Jurassic-Cretaceous boundary (Steel & Josephs Land in a southerly direction toward the Worsley 1984). These culminated in marked culmination between Hopen High and the Sen­ movements in the earliest Cretaceous with local tralbank High. contemporaneous breaks in deposition. They are also associated with the intrusion of dikes and sills of Berriasian age. North-south lineaments are also found east of Spitsbergen on seismic sections. The post Barremian (Cretaceous) The north-south extensional faults in the Spits­ rifting of the North Atlantic bergen area, of Neocomian age, are suggested (Phase IV) here to be associated with a northeast-southwest dextral wrench system in the southern Barents Post Neocomian basin development continued Sea (Fig. 11). essentially along lines established during Late This fault zone is thought to continue between Jurassic times. While the Neocomian (Phase Ill) the Sentralbanken High and Hopen High north­ sequences were preceded by the onset of sea-floor ward to a north-south lineament east of Kong spreading between the Azores and the Charlie Karls Land. Across the culmination, between Gibbs Fracture Zone, the post Neocomian Cre­ Hopen High and the Sentralbanken High, the taceous sand sequences were associated with the fault zone swings to a more north-south direction, onset of sea-floor spreading in the Bay of Biscay and falls into the pattern of Late Jurassic north­ and Rockall Trough (Roberts et al. 1981). south extensional faulting in the northern Barents Although Cretaceous rifting was common in 290 V. B. Larsen NORSK GEOLOGISK TIDSSKRIFf 67 (1987) several individual basins in Northwest Europe, transgressed by the Aptian-Albian Valhall For­ the dominant rift system was located from the mation. The East Shetland Platform and the Rockall Trough through the Færø-Shetland adjacent basins were therefore not receiving Channel, the Møre and Vøring Basins up to the Phase IV associated sandstones due to the limi­ Tromsø and Bear Isle Basins. Oceanic crust was tation of nearby exposed areas (provenance generated in the southern part, but became nar­ areas). rower northward and probably ended in the Møre Further east, however, north-south normal Basin. The rift/spreading system does not necess­ faulting along the coast of West Norway gave rise arily require a clockwise rotation of Greenland to Aptian-Albian sandy turbidites and fan delta and the Rockall Plateau, as suggested by Hanisch systems (Koppervik Formation and Florø For­ (1983). The rifting in Labrador-Baffin Bay and mation). These sands prograded toward the west the creation of oceanic crust in this aulacogen's as the Viking Graben was subsiding and the East southern part does not support such a model. The Shetland Platform was receiving the shaly Sola Late Cretaceous pull-apart basins in northeast Formation (Fig. 19). Greenland suggest the opposite, namely a con­ North of 62°N, similar Aptian-Albian sand­ tinuous anticlockwise rotation relative to Europe stones are expected to have developed along the of the Greenland Plate from the Kimmeridgian northeast-southwest fault system dose to the throughout Cretaceous times. Norwegian coast as well as along highs which The formation of oceanic crust in the Rockall were exposed at that time. The apex of the fan Trough, its width probably decreasing to the systems should be located at the kinks formed by north, may rather be explained by a net drift the intersection of north-south and northeast­ of the southwest European Plate eastward. The southwest fault systems. Because of the pro­ associated break-up and formation of the oceanic gressive northeast-southwest Cretaceous rifting, crust between West Africa and South America, younger turbidite/fan-delta systems should be and the anticlockwise rotation of the Iberian found further north along the rift system. Plate, all individually contributed to increased On East Greenland, Neocomian anticlockwise extensional forces in the southern part of the rotation of the Greenland Plate continued North Atlantic rift system. through the Aptian-Albian and Upper Cre­ taceous time, with a more northwesterly net movement. The Aptian sequences are found here Rift corresponding sand-distribution in lying with pronounced angular unconforrnity post-Barremian Cretaceous time above faulted Valangian or older rocks (Surlyk et The end of a compressional regime in the area al. 1981). The turbidites of Albian and Aptian west of Shetland resulted in the development of age in East Greenland are in concordance with thick clastic sequences. Fault movements were similar development (tectono-stratigraphic) to focused particularly on the Shetland Spine Fault the turbidites in the Færø-West Shetland Basins. adjacent to the southern end of the West Shetland and the Florø/Koppervik Formations in the Basin. The sandstones are interpreted as sub­ Norwegian North Sea. Recent drilling has also marine fans or fan delta systems (Ridd 1981). The proved similar sandstones to be present southwest Phase IV movements of these fault systems were of the Nordland Ridge. most active during Aptian-Albian time. It is also Extensional block faulting continued in East likely that the Færoe Basin subsided rapidly dur­ Greenland during 'the Upper Cretaceous, cli­ ing this time and was continuously supplied with maxed in Cenomanian and Middle Turonian time, sand. and produced more sandy turbiditic sequences . On the eastern side of the Shetland Platform, along the East Greenland margin (Donovan Lower Cretaceous sandstones in the Moray Firth 1957). An equivalent development has been Basin are referred to as the 'Unnamed observed on the Haltenbanken area and is also Formation'. These sandstones, however, are expected west of the Nordland Ridge. Such sand related to Phase Ill (Neocomian uplift), as they sequences are expected to be thicker and coarser are dated pre-Aptian and are overlain by Bar­ grained further north (e.g. west of the Lofoten remian limestones. The adjacent platform area, Isles) (Fig. 20). as well as the Tampen Spur, are capped by the In the dextral pull-apart basins in northeast same Barremian limestones which again are Greenland, which were associated with a con- NORSK GEOLOGISK TIDSSKR!Fr 67 (1987)

A SYNTHESIS OF TECTONICALLY-RELATED STRATIGRAPHY IN THE NORTH ATLANTIC-ARCTIC REGION FROM AALENIAN TO CENOMANIAN TIME

VIDAR B. LARSEN

(a colour insert) o STRATIGRAPHIC CORAELATION CHART RELATEO TO THE 4 TECTONIC PHASES

L:]SANDSTONE rr:::I:]CONGLOMERATE �LIMESTONE E3SILTSTONE �MAAL �SHALE (!;}HOTSHALE �TUFF ITjUMESTbNESTEAKES [[[I]NON OEPOSITION

Fig. l (above). Stratigraphic correlation chart related to the four tectonic phases. (Statoil data base.) (Note that in this figure the names suggested by the Norwegian Nomenclature Committee on Haltenbanken and Troms are used, while in the text and on the other figures the more established formation names are used.)

Ile Formation Lower Tomma Formation Gam Formation Upper Tomma Formation Spekk Formation Nesna Formation Rogn Formation Frøya Formation Hekkingen Formation Risfjord Formation Fuglen Formation Olderfjord Formation Kveite Formation Slettnes Formation

Fig. 2 (facing). Sand distribution related to Phase I tectonic, Late Middle Jurassic (ca. 170 Ma). - SUBAERIAL EXPOSED AREA - MARINE SAND - PLATFORM LIMESTONE /MARL - SHElF MUD/SILT - OEEP EP! CONTINENTAL SEOIMENTS

SINISTRA.L. FAULT • CONTINENT MOVEMENT o SEDJMENT TRANSPORT OIRECTION IGNEOUSo\CTIYITY o

PHASE l NORTH SEA

NNW o SSE 61"30' GULLFAKS OSEBERG BLOCK 30/11 SLEIPNEA FISKEBAN K DANISH SUB BASIN SUB BASIN

Qldordian C.llovian Bathonian

WNW ESE

STATFJORD GULLFAKS OSEBERG TROLL

NottOSCIII NOVA SCOTIA GRAND BANKS E. NEW FOUNDLAND BASIN Jeanne D'Arc Subbasin o

Southwllrdstransgr ession of ArgoS.h, an arm of Tnhys.

Nottoscale

Fig. 3 (Jacing above). Maximum distribution of Brent (Late Bathonian) delta in the northern North Sea. After L. Beck and M. Adachi.

Fig. 4 (facing below). Schematic stratigraphic cross-sections of the Middle Jurassic Brent delta in the northern North Sea.

Fig. 5 (above). Stratigraphic correlation chart, Southwest Area. Note the southward youngingof the Argo Salt and the nortbward younging of continental break-up. Fig. 6 (above). Land bridge between Vestfjorden and northeast Greenland during the transgression from the south, associated with clockwise rotation of the Greenland plate.

Fig. 7 (facing above). Schematic cross-section illustrating the relationship between the Pelion Member and the Upper Temma Formation.

Fig. 8 (facing below). Relation of doming and the regressive Wilhelmøya Formation in the northern Barents Sea in the Lower and Middle Jurassic time. Spitsbergen was an area of non-deposition and erosion in Rhaetian-Callovian time with min or extensional fault activity (sinistral). Tilting of fault block occurred from Callovian time. PHASE l o EAST GREENLAND

J

" Pel!on Mb." further north in Helgeland 6 Vntfjord Ba1in1 /� NORDLAND // / /l NORWAY ���� // l

NottOICI11

o PHASE l NORTHERN BARENTS SEA

w

Spittbllrgen Fr1nz- Victoria Trench Franz Josephs Land

Not to stall SHELFMUD/SILT

DEEI> EPICONTINENTAL SEDIMEN�TS'"

LATERAL FAUL T MOVEMENT • CONTINENT MOVEMENT o SEDIMENT TRANSPQRT DIRECTION IGHEOUS ACTIVITV o

w

NE GREENLAND SPITSBERGEN FRANZ -VICTORIA TRENCH FRANZ JOSEPHS LAND WANDELSEA

Nottoscale

Fig. 9 (facing). Sand distribution related to Phase Il tectonic, Upper Jurassic time (ca. 160 Ma).

Fig. JO (above). Relation between northeast Greenland-Spitsbergen and northeast Barents Sea during Phases l, Il and Ill. Phase I: Wilhelmøya Fm prograding from a dome in Franz Victoria Trench area towards west contemporaneously with deposition of Brentskardhaugen Beds in Spitsbergen. Phase Il:Collapse of the dome and creation of a NE-SW graben. Immediate transgression and deposition of Agardhfjellet Formation Shales (basic intrusives). Phases Iland Ill: Regressive sequences of sand deposits along the basin margins continuously shallowed the basin until Barremian time (basic intrusives). · SU8AERIAL E XPOSEO AREA

MARINE SAND llNCL ':'ER DELTAIC)

SHELF MUD l SILT l ORGANl C l

DEEP EPICONTINENTAL SEDIMENT$

SINISTRAL FAUL T

CONTINENT MOVEMENT

SEDIMENT TRANSPORT DIRECTION

IGN!OUSACTIVITY ':

PHASE Ill WEST SHETLAND RYAZANIAN- BARREMIAN o A A'

Barremianlimestone

U Jur Turb. Ryaum.lln & Volgum W.Shetland tnollic shale � Struct. high

Regional uplift & Compression

PREC. CARl. OEV.

...... -

Fig. Il (facing). Sand distribution related to Phase lii tectonic. Dextral transpression (NE-SW), due to anticlockwise rotation of the Greenland Plate, dominates the area from the Faeroe Basin in the south to the Sentralbank High in the north in Neocomian time.

Fig. 12 (above). Neocomian dextral compression resulted in shallowing and deposition of anoxic shale with overlying sandstones reworked from the structural highs (West Shetland). PHASE Ill NORTHERN NORTH SEA o

NW SE

TAMPEN SPUR NORTH VIKING GRABEN HORDA PLATFORM

Outral NE - SWwrenching.

Nottoscale

Fig. 13 (above). Northeast-southwest dextral wrenching led to uplift in northwest, erosion and deposition of pre-Barremian--post Early Kimmeridgian shallow marine sandstones (northern North Sea).

Fig. 14 (below). Northeast-southwest regional dextral wrenching resulted in uplift, shallowing and deposition of anoxic shale with overlying and interfingering sandstones reworked from the structural highs (West Norway East-Greenland).

PHASE Ill

LOWER KIMMERIOGIAN - BARREMIAN

NW

EAST GREEN LAND VORING BASIN WEST NORWAY (HALTENBANKEN)

NET UPLIFT

Nottoscale PHASE Ill o

MILNE LAND S. JAMESDN LAND

NW SE

Fig. 15 (above). East-Greenland uplift and compression in Volgian time is related to regional dextral nDrtheast-southwest wrenching in the North Atlantic. (l) Salix Dal of Raukelv Formation is thinning (wedges out) southward and consists of grey to black uniform micaceous silty shale. (2) Raukelv Formation (shallow marine) Dverlies Hareelv Formation (deep marine). (3) Gråkloft Member of Kap Leslie Formation (K.immeridgian). is deposited during the transition from deep marine (Hareelv Formation) to shallow marine Raukelv Formation.

Fig. 16 (be/ow). Schematic sketch of the relationship between northeast Greenland and Spitsbergen in Late Jurassic-pre-Aptian time.

PHASE Ill

WANDEL SEA SPITSBERGEN o NE GREENLAND EXTENSIONAL TECTONIC AS IN PHASE 11 EXTENSIONAL TECTONIC

w

Fm.

Not to telle o

Notto stalt

o w

Nottosc.lt PHASE IV o

w

FAEROE BASIN WEST SHETLAND SHETLAND EAST SHETI.AND NORTH VIKING GRABEN SOGN GRABEN NORTH

Nottoscale

Fig. 17 (facing above). Schematic cross-section through the Labrador shelf. Redrawn from McWhae (1981). Freydis Member: Nearshore sands. Bjarni Fm: Thick continental molasse deposits (Late Neocomian-Aibian) 100-3000m thick. No Jurassic encountered. Alexis Fm: Igneous dikes and extrusive volcanic rocks associated -with major gra ben faults.

Fig. 18 (facing below). Lithostratigraphic cross-section of the Scotian Shelf and Slope. Redrawn from Jansa & Wade (1975). The porous sandstone MissisaugaFormation is deposited in a deltaic setting at the same time as the continental Bjarni Formation on the Labrador Shelf (Upper Neocomian, Phase Ill).

Fig. 19 (above). Schematic cross-section from Faeroe Basin in the west to Sogn Graben in the east. Note the Neocomian sandstones located along the Shetland highs.

Fig. 20 (nextpage). Sand distribution related to Phase IV tectonics. The area is within an extensional tectonic regime and turbidites along the continental margins are common. (Late Lower Cretaceous-early Upper Cretaceous.) SUBAERIAL EXPOSEO AREA

MARINE SAND (INCL UPPER DEL TA/C l

DEEP EPICONTINENTAL SEDIMENTS

OCEANIC CRUST

SINISTRAL FAUL T

• CONTINENT MOVEMEI'fT o SEDIMENT TRANSPORT OHlECTtON

IGNEOUS ACTIVITY NORSK GEOLOGISK TIDSSKRIFT 67 (1987) TSGS Symposium 1986 291

tinuous anticlockwise rotation of the Greenland A rift basin is suggested to have existed in the Plate in Phase IV, rather immature sediments North Atlantic in Late Jurassic time from Rockall ·are preserved (Nakkekoved/Herlufsholm Strand to the Barents Sea. Turbidities in the southwest Formations). This led to the interruption of the were deposited at the same time as the shallow eastward progressive Ladegaardsaaen Formation marine Sognefjorden Formation in quadrants 31 which bad prograded eastwards in response to and 32 on the Norwegian Shelf, turbidites on Phase Il and Phase Ill tectonics from Middle East Greenland as well as shallow marine sands Oxfordian time into the Barremian-Lower in Sverdrup Basin and Wandel Sea. These are Aptian part of the Helvetiafjellet Formation on all results of the same plate tectonic movements Spitsbergen (Fig. 16) (Neocomian, Phase Ill (Phase Il) the Jurassic rifting in Callovian­ delayed). It is even more delayed in the Canadian Kimmeridgian time (Fig. 9). Arctic Isles, Sverdrup Basins, where the non­ The change in the tectonic pattem by an anti­ marine Isaksen Formation (Embry 1985b) con­ clockwise rotation of the Greenland Plate, tinues up into Upper Aptian time (Fig. 1). resulted, due to compression, in shallowing of The dextral pull-apart basins were also associ­ many basins between West Shetland and the ated with a regional uplift in the northemmost Troms area. The same plate tectonic movement Barents Sea along the paleoposition of the created extensionally related sedimentation; Lomonosov Ridge. This led to a shift in the pro­ Upper Awingak Formation (Sverdrup Basin) and . gradational direction of the Cretaceous sand- Ladegaardsaaen Formation (Wandel Sea) as well stones in Spitsbergen. The sands of the as extensional tectonic on Spitsbergen (Phase Ill, Helvetiafjellet Formation were transported from Fig. 11). the west (from Ladegaardsaaen Formation), Northwest movement of the Greenland Plate while provenance for the overlying Carolinefjellet with a slight rotation anticlockwise as well as a net Formation was the uplifted area in the north. The drift of the southwest European plate eastward uplift caused a transgression and deposition of resulted in formation of oceanic crust on the marine shales upon the sandy sequences in North­ Rockall Trough and associated turbiditic east Greenland and Sverdrup Basin. Continuous sequences along the Norwegian-Greenland Sea rotation of the Greenland Plate with associated margins (Fig. 20). Pull apart basins in Wandel block faulting preserved Upper Cretaceous sedi­ Sea and dextral wrenching in western Barents Sea ments in these basins. Uplift and associated vol­ are also results of the same plate tectonic phase. canism along the northem edge of the Barents Sea The uplift-associated Carolinefjellet Formation in led to non-deposition of post Albian sediments in Spitsbergen, however, is govemed by another Spitsbergen, in spite of worldwide transgression, plate tectonic history, the development of the lasting until Paleocene time. Polar Basin. The four different tectonic phases described here are shown to be closely related to cor­ responding sandstone distributions, and may Conclusions serve as a guideline in future exploration for A provenance area for sand is suggested to have reservoir targets. existed during Late Middle Jurassic time in the Acknowledgements. -I thank the management of Statoil explo­ area between Hochstetter Foreland and Lofoten, ration for perrnission to publish this paper and acknowledge giving rise to rather thick fan delta sediments in many helpfuldiscussions with geologists from Statoil and Arco. both Mid Norway (Upper Tomma Formation) I also direct my thanks to Sidsel Haugland and Terje Vågenes, and East Greenland (Pelion Member), as well who did the dratting, and to Turid Normann, who typed the manuscript. as in the Troms Area (Stø Formation). These sandstones are deposited at the same time as the Tarbert Formation in the North Sea, Hiccles Cove Formation in the Sverdrup Basin and the car­ bonate platform in the Grand Banks Area. They References are all indirectly the result of the same plate Aasheim, S. M. & Larsen, V. 1984: The Tyrihans discovery­ tectonic movement (Phase I), a clockwise rotation Preliminary results from the well 6407/1- 2. In Spencer, A. of the North American/Greenland Plate (Figs. 2, M. (ed.): Petroleum Geology of the North European Margin. 1). 271-283. Norwegian Petroleum Society. 292 V. B. Larsen NORSK GEOLOGISK TIDSSKRIFT 67 (1987)

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