Wandel Basin: basin analysis - a summary

Eckart Hakansson and Lars Stemmerik

In 1991 a three year research project was initiated by the terised by a simple system of grabens and half-grabens Geological Institute, University of Copenhagen with finan­ developed parallel to the craton margin, and a later Mesozoic cial support fromthe Ministry of Energy, the Danish Natu­ epoch dominated by strike-slip movements which in part ral Science Research Council and the Carlsberg Foundation. reactivated existing extensional faultsystems (Hakansson & The 'Wandel Sea Basin: basin analysis' project was car­ Stemmerik, 1989). ried out in collaboration with the Geological Survey of In pre-drift reconstructions the Wandel Sea Basin is and included fieldwork in North Greenland; in located in close proximity to the Sverdrup Basin of eastern in 1991 and Amdrup Land in 1993 Canada, and the sedimentary basins of and the (Fig. 1; Hakansson etal., 1994). Barents Shelf. It is closely related to these basinal areas. The project is a continuation of earlier investigations in the Pronounced differences exist, however, both in terms of Wandel Sea Basin carried out during geological mapping of basinal dynamics and depositional character. Most differ­ North Greenland by the Geological Survey of Greenland in ences are directly related to the development of a strike­ 1978-1980 and during later expeditions to the area (e.g. slip dominated plate boundary across the north-eastern Hakansson, 1979; Hakansson et al., 1981, 1989, 1991, comer of Greenland within the Mesozoic: the Wandel Hav 1994 ). Hydrocarbon related studies of the Wandel Sea Ba­ strike-slip mobile belt. When substantial plate reorganisa­ sin were continued during the 1994 field season (Stem­ tion commenced in this part of the Arctic, with the initia­ merik et al., this report) and further activities are planned tion of the North Atlantic and Arctic , the plate for the 1995 season. boundary separating Greenland and shifted to its The main purpose of the project was to provide detailed present position, and activity ceased in the Wandel Sea sedimentological and biostratigraphical data for an im­ Basin area. proved evaluation of the hydrocarbon potential onshore eastern North Greenland, and to evaluate the structural history of the basin in order to understand the distribution Upper Palaeozoic of the now scattered sedimentary outcrops. The completed Biostratigraphic studies have been concentrated mainly report comprises 22 technical reports and 4 appendices in the mid-Moscovian to Kazanian succession of eastern (Hakansson et al., 1994). Peary Land, while new sedimentological data have been obtained from both eastern Peary Land and from Amdrup Land (Stemmerik & Elvebakk, 1994; Stemmerik et al., Geological overview 1995, in press). The new biostratigraphic and sedimento­ The Wandel Sea Basin was an area of accumulation logical data have greatly improved understanding of the throughout the Early Carboniferous- Early Tertiary, located depositional and tectonic evolution of the Wandel Sea Ba­ at the north-eastern margin of the stable Greenland craton sin during the Upper Palaeozoic (Fig. 2). where the Caledonian and Ellesmerian fold belts intersect The marine Moscovian to Kazanian succession is com­ (Fig. I). The sedimentary succession rests with a regional posed of three major depositional units that can be corre­ unconformity on a mosaic of Precambrian to Silurian lated with sedimentary units in Arctic Canada, Svalbard rocks,. which have been in part deformed by either the and the . Large scale correlation between these Caledonian or Ellesmerian orogenies. Deposition has largely areas has previously been suggested, but the improved been confined to a fairly narrow fringe along the Green­ biostratigraphic framework allows correlation on a more land craton delimited by three major fault zones: the detailed scale (Stemmerik & Worsley, 1989, 1995; Nils­ Harder Fjord faultzone, the Trolle Land faultzone, and the son, 1994). Although the Wandel Sea succession to some East Greenland faultzone (Fig. 1). degree resembles the equivalent successions in the Arctic Two main but unrelated epochs in basin evolution have , new biostratigraphic data also indicate some major been distinguished, an early Late Palaeozoic epoch charac- differences. The most important are:

Rapp. Gr�nlands geol. Unders. 165, 42-48 ( !995) © GGU, Copenhagen, 1995 43

25'

Prlnsesse Ingeborg Halvo

Fig. I. Simplified map showing distribution of Wandel Sea Basin ,edirnent,. HFFZ: Harder Fjord □ Tertiary f'auh zone: EGFZ: East Greenland □ Mesozoic fault wne: KCTZ: Kap Cannon D Upper Palaeozoic thrust zone: TLFZ: Trolle Land Faull Zone.

The mid-Carboniferous trnnsgression in North Green­ been identilied and conclation lO adjace111 areas can be land is Moscovian. The first marine pulse is Serpuko­ established on zone level. vian in the Sverdrup Basin while the main transgres­ The Moscovian succession is up to 600 m thick and was sion in the Sverdrup Basin and Spitsbergen took place deposited during a period with increased subsidence in the during late Bashkirian rifting. Wandel Sea Basin. Small scale block faulting has prcvi­ ou�ly been recorded from this pan or the succession. and Asselian and early Sakmarian deposit� have a re�trict­ the depositional patterns appear to some degree to be fault ed disu·ibution in the Wandel Sea Basin where they are controlled. Jn most areas the Moscovian succession is limited to the highly tectonised outcrop. on Prinsesse composed of stacked cycles of interbedded shelf carbon­ Ingeborg Halvc;.These units are missing on Bj13rnr1ya. ates and shallow marine sandstones (Fig. 3). In southern but elsewhere in the Arctic region two transgressive­ Amdrup Land carbonate build-ups are common in the Mos­ regressive cycles were deposired during this time inter­ covian succession. and occasionally they stack to formup lo val (e.g. Beauchamp et al .. 1989). I 00 m high, carbonate dominated platforms. Deposition took place in a semi-arid climate and Jolomitismion is Lower Artinskian deposits are missing in the Wandel widespread. Sea Basin. Elsewhere in the Arctic region. the early The Moseovian succession in Amclrup Land is mm­ Artinskian forms a large scale transgressive-regressive posed of seven third order depositional sequences (Stcm­ cycle. Both in the Barents Sea and in the SverdrnpBasin mcrik. 1994). They fonn an overall retrogradational succes­

major bryozoan-T11biphy1es build-ups fo1med during sion with maximum flooding during the latest Moscovian. this time interval (e.g. Beauchamp. 1993). The overlying latest Moscovian to Gzelian succession is highly progradation::iland forms an overall regressive unit. The Kasimovian-Gzelian succession is composed of Late Carbo11�fero11s (Moscol'ia11-Gze/ia11) stacked shoaling upward carbonate cycles throughout The Moscovian LO Gzelian succession forms i.l large Nonh Greenland. locally with abundant Palaeoaplysina scale transgressive-regressive unit which is separated from and phylloid algae build-ups (Stemmerik & El vebakk. the overlying Permian deposits by a major hiatus. A com­ 1994 ). The succession is capped by a major karst urface in parable transgressive-regressive dcvclopmen1 is seen in eastern Peary Land, Amdrup Land and Holm Land. and in the Sverdrup Basin (Beauchamp e1 al., 1989). on Bjprn0ya these areas most of the Lower Permian is missing. (Worsley e1 ul.. 1990) and on the Finnmark Platform Source rocks have not been identified in the Moscovian (Bugge e1 al., 1995). Dating of the Moscovian to Gzelian to G7elian succession in North Greenland. However, Lhe succession is based on fusulinids (Nilsson. 1994: Stem­ abundance of carbonate builtl-ups and widespread doln­ merik el al.. 1995, in press). Six local fusulinid zones have mitisalion makes this succession a good reservoir unit. In 44

Wandel Sea Basin

Age ___,. rf Ma TERTIARY ___,. � 75 (/) Late E3 .... , ...... :::> , .. •. • , . • ,::, D 0 w ,;·::.·.·: ;,·,;··c:;,,; 100 O � 11:··1·•.·.: .._----- rf w er: 0 Early

Late

L__ 0 rf� Middle Q) Q) -0 -0 C: C: C: Cl) 0 0 -0

Late � <( � Early • 300 0 Late

0 Early <( 350 0 Fig. 2. Simplified stratigraphy of the Wandel Sea Basin succession. eastern Peary Land an isolated Palaeoaplysina build-up mussen & Hakansson, submitted manuscript). Age assign­ contains bitumen and has once acted as a reservoir for ments based on small foraminifera and palynomorphs are hydrocarbons. less precise and correlation within this part of the succes­ sion is generally on stage level. The succession is dominated by shallow shelf carbon­ Mid-Permian (Late Artinskian - Kungurian) ates in southern Kim Fjelde, and on Amdrup Land. These In eastern Peary Land and on Amdrup Land and Holm sediments contain a distinctive fauna with large productid Land, late Artinskian deposits directly overlie Gzelian car­ and spiriferidbrachiopods, and large trepostome bryozoans. bonates. This transgressive event can be correlated with In northern Kim Fjelde, the succession is dominated by major transgressions in the Sverdrup Basin, and the sedi­ finely bedded resedimented carbonates with abundant mentary basins of Svalbard and the Barents Sea (Stem­ chert. In this area the succession shows a gradual upward merik & Worsley, 1995). The upper Artinskian to Kunguri­ deepening, and the upper Kungurian part is dominated by an succession is dated by a combination of conodonts, interbedded chert and shale. Deposition of this unit small foraminifera and palynomorphs (Stemmerik et al., in appears to have been related to large scale subsidence and press). Conodonts are rare in the Wandel Sea Basin succes­ tilting of the Wandel Sea Basin, as is the case in other sion, and only one conodont zone has been identified (Ras- basins in the Arctic region. This tectonic event was associ- 45

---=-

Fig. 3. Upper Carboniferous. Moscovian-Glhelian sedi 111ents in eastern Holm Land. The lower pan consists of cyclic interbedded shelf carbonates and siliciclastic deposiis: the upper part is dominated by shelf carbonates. Cliff height is approximately 350 m. ated with a major change in climate or circulation. In the Kazanian succession is composed of two shallowing Wandel Sea Basin the mid-Permian fauna differs signifi­ upwards cycles of deeper water shalcs and inner shelf cantly from that seen in the underlying Foldedal Forma­ carbonates or she! f sandstones. tion: deposition apparently took place in a relatively cold, The b<1sal parts of the two cycles consist of black lami­ temperate climate. nated and bioturbated shales. These shales have low organ­ The change in climatic conditions prior to deposition of ic content and little potential as source rocks for hydrocar­ the late Artinskian carbonates is reflected by diagcnetic bons. The shales are overlain by bryozoan and brachiopod processes which have had influence on the reservoir poten­ dominated shallow marine limestones with abundant chert tial. Most carbonates are cemented by stable low-Mg calcite in south-eastern Kim Fjelde. In northern Kim Fjelde the or chert and there is little or no porosity in the rocks. A shales pass upwards into a thick succession of bioturbated similar pattern is seen in the Barents Sea area; Artinskian she! r sandstone. and younger Permian carbonates appear to have little eco­ The limestones were deposited under climatic condi­ nomic potential in the Arctic region. tions similar to those dominant during the Kungurian and have little or no porosity. This unit therefore has very lim­ ited reservoir potential.

LateThe Permian succession ( Ka-;,anian) in Kim Fjelde, eastern Peary Land is dated on the basis of small foraminifcra and palynomorphs Mesozoic to Paleogene as Kazanian; a more precise age assignment is not possi­ ble. The base of the Kazanian is a major flooding surface that marks a rapid drowning of the depositional basin EarlyEarly Triassic Mesozoic sedimentation in the Wandel Sea Basin (Fig. 4). In south-eastern Kim Fjelde large scale resedi­ was apparently restricted to the Skythian-Anisian. Two mentation and slumping of carbonates suggest that this shallowing upward sequences are distinguished in the drowning event was associated with active faulting. The Peary Land area. the Parish Bjerg and Dunken Formations. 46 The Parish Bjerg Formation rests on Palaeozoic sediments tions throughout the Early Cretaceous, whereas terrestrial with a low angle unconformity, whereas the relationship conditions prevailed in the Peary Land region until late in between the Parish Bjerg and Dunken Formations is not the Aptian. discernible in the field. Both sequences show evidence of Oil source rocks with economic potential have not been rapid deepening with thin intervals of deep-water turbiditic found in the Jurassic-Cretaceous succession of the Wandel facies rapidly giving way to silty and sandy shales with Sea Basin. Very subordinate, thin shale beds with source gradually increasing sand content. Mid- to shallow shelf rock quality (HI > 100) do occur in the Jurassic - Lower conditions were maintained throughout deposition of the Cretaceous sequence but are not widespread. By contrast, thick sands forming the top of both sequences. The pres­ widely distributed mid-Cretaceous shales do not have ence of reasonably well preserved macro-plant fossils in source quality, as the organic content is terrestrially de­ the Anisian sandstone may point to deposition on a fairly rived. narrow shelf. The age of the two transgressive-regressive cycles recorded in the Parish Bjerg and Dunken Formations is not Late Cretaceous - Early Tertiary particularly well documented. However, newly collected The Late Cretaceous Kilen event is the second major ammonites from the lower part of the Dunken Formation episode along the strike-slip mobile belt. It is dominated by indicate the presence of the Skythian Euflemingites romun­ dextral strike-slip movements in an overall extensional re­ deri Zone, and it thereforeseems likely that both flooding gime, leading to the formation of at least six fairly small, events took place during the Skythian. The shelf sands of rapidly deepening pull-apart basins across North Green­ the Dunken Formation contain an Early Anisian faunain land, each with a marine depositional signature (Hakans­ their lower part; very poorly preserved ammonite faunas son & Pedersen, 1982; Birkelund & Hakansson, 1983). fromthe top of the formationindicate that deposition was Two of these basins remained terrestrial throughout their terminated in the early part of the Anisian. entire history, one is mixed terrestrial-marine, while three Shales from the Triassic Dunken Formation generally remained marine. There is nothing to indicate that any have very low contents of organic matter ( <0.25%) of mixed direct connection existed between these basins, nor do they terrestrial and marine composition. The organic content is have any obvious relationships to basins outside North mature with respect to oil generation, with a Hydrogen Greenland. However, comparatively small basins on the Index (HI) of 100 on average. Barents Shelf which contain Upper Cretaceous strata may be structurally related to the series of pull-apart basins in North Greenland. All basins have been disturbed by subse­ Late Jurassic - Early Cretaceous quent compression, and all Upper Cretaceous sediments in No sediments are preserved from the long interval of North Greenland have suffered severe thermal degrada­ time between the Anisian and the Oxfordian(Fig. 2), and it tion. is most likely that the strike-slip regime of the Wandel Hav Two basins are located in Kronprins Christian Land. The strike-slip mobile belt governing the remaining part of the Kilen Basin contains at least 1500 m of marine sediments Wandel Sea Basin history was established during this of Middle Turonian to Early Coniacian age which docu­ period. There is some evidence to suggest repeated activity ments several pulses of basin deepening. The Nakkehoved in the Trolle Land fault zone throughout the period, but the Basin contains at least 600 m of marine sediment, but the first clearly discernible event is the extensional Ingeborg sparse bivalve fauna does not permit an age determination event, which locally created subsidence of the order of 1-2 better than Late Cretaceous. The remaining basins are all km along normal listric faults. Related compressive struc­ located in Peary Land. The Herlufsholm Strand Basin in tures in Kim Pjcldc point to a sinistral transpressive ele­ easternPeary LanJ is strongly fukk

Fig. 4. Bedded chert-rich carbonates of the Kim Fjclde Formation abruptly overlain by black laminated shalcs of the Midnatfjeld Fom1ation renecting a major Late Permian drowning event in the Wandel Sea Basin. Late Santonian fauna. The Kap Washingto11 Basin at the substantial sedimentary succession been documented. The north coast of Peary Land is bordered by the Kap Cannon thermal history revealed by the Wandel Sea Basin sedi­ thrust zone to the south. This basin contains in the order of ments has therefore been found to be influenced more by 5 km of extrusive volcanic rocks and volcanogenic sedi­ particular thermal events than by their burial history. ments, with a few intervals of fluvial sediments. Upper Two significant events may be distinguished. One ther­ Cretaceous plant fossils occur at several levels, and the top mal pulse in the end-Cretaceous is related to the contrac­ of the volcanic suite has been dated to about the Creta­ tional forces which caused considerable thermal alteration ceous-Tertiary boundary. (locally reaching grccnschist facies) in areas of maximum All Upper Cretaceous deposits in North Greenland have compression. The second pulse occurred later in the Terti­ suffered compressional deformation to a varying degree. ary, after sediment accumulation in the Wandel Sea Basin While compression in the main Wandel Sea Basin, in east­ had ceased, and was focused in northern Kronprins Chris­ ern Peary Land and Kronprins Christian Land, took place tian Land; its source remains uncertain. close to the Cretaceous-Tertiary boundary, compression along the Harder Fjord fault zone and the Kap Cannon thrust zone may have occurred later in the Tertiary as pan Hydrocarbon potential of the Eurekan orogeny. The onshore parts of the Wandel Sea Basin are thought Post-compressional late Paleocene - early Eocene flu­ to have limited hydrocarbon potential on the basis of present vial plain sediments with locally abundant plant debris are investigations. The main problems are thermal maturity largely restricted to the central part of the Trolle Land fault and the absence of any obvious source rocks within the system. The facies distribution indicates an overall drain­ basin. age towards the south and south-west. Carboniferous to Cretaceous sediments exposed in north­ Subsidence rates varied greatly during the Mesozoic due ern Kronprins Christian Land are thermally post-mature to the differential movements along the Trolle Land fault due to local heating. While these areas are unprospective system, and only in the Kilen area has the presence of a due to increased heating, southern Kronprins Christian 48

Land, Amdrup Land and Holm Land suffer from lack of Hakansson, E., Heinberg,C. & Stemmerik, L. 1991: Mesozoic adequate burial. Here the Carboniferous-Permiansediments and Cenozoic history of the Wandel Sea Basin area, North are immature to early mature at surface and have never Greenland. Bull. Gr�nlands geol. Unders. 160, 153-164. Hakansson, E., Birkelund, T., Heinberg,C., Hjort, C., Mplgaard, been buried deeply enough to generate hydrocarbons. P. & Pedersen, S. A. S. 1993: The Kilen Expedition 1985. So far, no laterally persistent organic-rich units have Bull. geol. Soc. Denmark 40, 9-32. been identified within the Carboniferous to Cretaceous Hakansson, E., Heinberg, C., Madsen, L., M\Zilgaard, S., Peder­ succession in eastern Peary Land, and exploration models sen, S. A. S., Piasecki, S., Rasmussen, J. A., Stemmerik, L. & have to rely on sourcing from older, Cambrian or Silurian Zinck-J\Zirgensen, K. 1994: Wandel Sea Basin: Basin Analy­ organic-rich shales in this region. The Lower Palaeozoic sis. EFP-91 Project No. 0012;Completion report to the Min­ sediments directly beneath the Wandel Sea Basin are ther­ istry of Energy. Unpublished report, Geological Institute, University of Copenhagen, 400 pp. mallypostmature with respect to hydrocarbon generation, Nilsson, I. 1994: Upper Palaeozoic fusulinid assemblages, Wan­ and exploration models have therefore to involve large del Sea Basin, North Greenland. Rapp. Gr�nlands geol. scale lateral migration. Models relying on sourcing from Unders. 161, 45-71. older sediments cannot be used in Holm Land andAmdrup Rasmussen, J. A. & Hakansson, E. submitted MS: First Permo­ Land where the succession rests directly on Caledonian­ Carboniferous conodonts from North Greenland. Submitted affectedbasement. to Geol. Mag. While the onshore potential of the basin seems to be Stemmerik, L. 1994: Sequence stratigraphy of a mixed carbon­ ate, siliciclastic and evaporite succession, Upper Carbonifer­ limited, the succession appears to have much higher poten­ ous, North Greenland. In High resolution sequence stratigra­ tial offshore northern EastGreenland. Increased knowledge phy: Innovations and applications. Abstract Volume, 159-160. of the basin history and structural style within the onshore Liverpool: University of Liverpool. basin will improve evaluation of these offshoreareas. Stemmerik, L. & Elvebakk, G 1994: A newly discovered mid­ Carboniferous - ?Early Permian reef complex in the Wandel Sea Basin, easternNorth Greenland. Rapp. Gr�nlands geol. References Unders. 161, 39-44. Stemmerik, L. & Worsley, D. 1989: Late Palaeozoic sequence Beauchamp, B. 1993: Carboniferous and Permian reefs of Sver­ correlations, North Greenland, Svalbard and the Barents Shelf. drup Basin, Canadian Arctic: an aid to Barents Sea explora­ InCollinson, J. D. (ed.) Correlation in hydrocarbonexplora­ tion. In Vorren, T. 0. et al. (ed.) Arctic geology and petrole­ tion, 99-111. London: Graham & Trotman for the Norwegian um potential. Spee. Puhl. Norwegian Petrol. Soc. 2, 217-242. Petroleum Society. Beauchamp, B., Harrison, J.C. & Henderson, C. M. 1989: Up­ Stemmerik, L. & Worsley, D. 1995: Permian history of the Bar­ per Paleozoic stratigraphy and basin analysis of the Sverdrup ents Shelf area. In Scholle, P.A., Peryt, T. M. & Ulmer-Scholle, Basin, Canadian Arctic Archipelago: Part 2, Transgressive­ D. S. (ed.) The Permian of northern Pangea 2: Sedimentary regressive sequences. Geol. Surv. Canada Pap. 89-lG, 105- basins and economic resources, 81-97. Berlin: Springer Ver­ 113. lag. Birkelund, T. & Hakansson, E. 1983: The Cretaceous of North Stemmerik, L., Nilsson, I. & Elvebakk, G. 1995: Gzelian-Asse­ Greenland - a stratigraphic and biogeographical analysis. Zit­ lian depositional sequences in the western Barents Sea and teliana 10, 7-25. North Greenland. In Steel, R. et al. (ed.) Sequence stratigra­ Bugge, T., Mangerud, G., Elvebakk, G., M\Zirk, A., Nilsson, I., phy on the northwest European margin. Spee. Puhl. Norwe­ Fanavoll, S. & Vigran, J. 0. 1995: The Upper Paleozoic suc­ gian Petrol.Soc. 5, 529-544. cession on the Finnmark Platform, Barents Sea. Norsk Geol. Stemmerik, L., Hakansson, E., Madsen, L., Nilsson, I., Piasecki, Tidsskr. 75, 3-30. S., Pinard, S. & Rasmussen, J. A. in press: Stratigraphy and Hakansson, E. 1979: Carboniferous to Tertiary development of depositional evolution of the Upper Palaeozoic sedimentary the Wandel Sea Basin, eastern North Greenland.Rapp. Grr/m­ succession in eastern Peary Land, North Greenland. Rapp. lands geol. Unders. 88, 73-83. Gr�nlands geol. Unders. Hakansson, E. & Pedersen. S. A. S. 1982: Late Paleozoic to Ter­ Worsley, D., Agdestein, T., Gjelberg, J. & Steel, R. J. 1990: Late tiary tectonic evolution of the continental margin in North Palaeozoic basinal evolution of Bjpm\Ziya:implications for the Greenland. Can. Soc. Petrol. Geol. Mem. 8, 331-348. Barents Sea. Geonytt 1, 124-125. Hakansson, E. & Stemmerik, L. 1989: Wandel Sea Basin - A new synthesis of the late Paleozoic to Tertiary accumulation in North Greenland. Geology 17, 683-686. E. H., Geological Institute, (Jster Voldgade JO, DK-1350 Hakansson, E., Heinberg, C. & Stemmerik, L. 1981: The Wan­ Copenhagen K, Denmark del Sea Basin from Holm Land to Lockwood 0, eastern North L. S., Geological Survey of Denmark and Greenland, Copenhagen Greenland. Rapp. Gn/mlands geol. Unders. 106, 47-63. Hakansson, E., Madsen, L. & Pedersen, S.A.S. 1989: Geologi­ cal investigations of Prinsesse Ingeborg Halv\Zi,eastern North Greenland. Rapp. Gr�nlands geol. Unders. 145, 113-118.