Geology of Greenland Survey Bulletin was published by the Geological Survey of Greenland (GGU) between 1997 and 2002. It consists of 18 printed volumes of peer-reviewed monographs and research articles relevant to Greenland geology and gesocience. This series replaced two earlier series: Grønlands Geologiske Undersøgelse Bulletin (1948–1996) and Grønlands Geologiske Undersøgelse Rapport (1964–1996). GGU merged with the Geological Survey of Denmark (DGU) in 1995 to form a single organisation, GEUS. The two surveys maintained their own scientific series until these too were merged into one, GEUS Bulletin, in 2003. Geology of Greenland Survey Bulletin is discontinued and is not open for submissions.
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Precambrian geology of the northern Nagssugtoqidian orogen, West Greenland: mapping in the Kangaatsiaq area
The Nagssugtoqidian orogen and its transition into the Rinkian orogen to the north were the main focus of the field activities of the Geological Survey of Denmark and Greenland (GEUS) in West Greenland in the summer of 2001. This work was carried out within the framework of the Survey’s three-year programme of bedrock mapping and mineral resource evaluation to enhance the understanding of the Archaean and Palaeoproterozoic crustal evolution in the transition zone between the Nagssugtoqidian and Rinkian orogens (Fig. 1). The work in the field season of 2001 comprised geological mapping of the 1:100 000 Kangaatsiaq map sheet described in this paper (Fig. 2), an investigation of the supracrustal rocks at Naternaq / Lersletten (Østergaard et al. 2002, this volume), a geochronological reconnaissance of the southern Rinkian orogen in the northern Disko Bugt region (Garde et al. 2002, this volume), a resource evaluation of the Nagssugtoqidian orogen (Stendal et al. 2002, this volume), a synthesis and interpretation of geophysical data of the central part of the Nagssugtoqidian orogen (Nielsen et al. 2002, this volume) and a report on investigations of the kimberlites and related intrusive rocks in the southern Nagssugtoqidian orogen and its foreland (Jensen et al. 2002, this volume).
The Precambrian supracrustal rocks in the Naternaq (Lersletten) and Ikamiut areas, central West Greenland
Naternaq, or Lersletten, in central West Greenland is an extensive Quaternary outwash plain characterised by light grey, silty sediments. Scattered low hills with outcrops of crystalline Precambrian basement rocks protrude from the outwash plain and form the northern part of the Nagssugtoqidian orogen (e.g. Connelly et al. 2000). The prominent Naternaq supracrustal belt, at least 25 km long and up to c. 2 km wide, occurs along the north-western margin of Lersletten, bordered on both sides by Archaean orthogneisses and granitic rocks; the supracrustal rocks outline a major fold structure with an irregular and sporadically exposed hinge zone (Fig. 1). The supracrustal rocks, including the fold closure, exhibit a negative signature on the regional aeromagnetic map (Fig. 2). The belt is known for its disseminated and massive iron sulphide mineralisation with minor copper and zinc, which is common in the south-eastern part of the belt.
A coastal survey in the southern part of the Palaeoproterozoic Rinkian fold belt, central West Greenland
A brief but potentially important part of the 2001 field investigations in the Precambrian of West Greenland (van Gool et al. 2002, this volume) was devoted to the southernmost part of the Palaeoproterozoic Rinkian fold belt east of Disko Bugt (Fig. 1). From 9–17 August the five authors carried out a reappraisal of critical Archaean and Proterozoic relationships and collected samples for precise geochronological studies. The principal aims are to date the main Rinkian tectonic and metamorphic events in this region as precisely as possible and compare them with the evolution of the Nagssugtoqidian orogen to the south (see van Gool et al. 2002, this volume, fig. 1). The vessel M/S Søkongen provided logistic support; a helicopter provided transport to Nunatarsuaq.
The mineral resource potential of the Nordre Strømfjord – Qasigiannguit region, southern and central West Greenland
Assessment of the mineral resource potential of the region between Sukkertoppen Iskappe and the southern part of Nuussuaq, West Greenland (66°N to 70°15´N; Fig. 1) is part of a regional resource assessment programme of the Geological Survey of Denmark and Greenland (GEUS) for 2000–2003. The year 2000 was dedicated to the compilation of existing data and the outlining of target areas for the field work in 2001 and 2002. This report gives a review of the work related to the gold and base metal potential in the Nordre Strømfjord – Qasigiannguit region, mainly based on results from the 2001 field work. Significant geological data have been collected from the region by the Survey, research groups and exploration companies during the past several decades; see Kalsbeek & Nutman (1996), Connelly & Mengel (2000) and van Gool et al. (2002, this volume) for geology, Steenfelt (2001) for geochemistry and Rasmussen & van Gool (2000) and Nielsen & Rasmussen (2002, this volume) for geophysics. Most of the region is easy of access, and exposures are excellent along the shores of the numerous fjords. However, inland areas may locally have extensive Quaternary cover.
Geological correlation of magnetic susceptibility and profiles from Nordre Strømfjord, southern West Greenland
The Palaeoproterozoic Nagssugtoqidian orogen is dominated by reworked Archaean gneisses with minor Palaeoproterozoic intrusive and supracrustal rocks. The Nagssugtoqidian orogen (Fig. 1) was the focus of regional geological investigations by the Geological Survey of Denmark and Greenland (GEUS) in 2001 (van Gool et al. 2002, this volume). In conjunction with this project, geophysical studies in the inner part of Nordre Strømfjord, Kuup Akua and Ussuit were undertaken as part of the Survey’s mineral resource assessment programme in central West Greenland. The studies include geophysical modelling of airborne magnetic data, follow-up studies of aeromagnetic anomalies by magnetic ground surveying, and geostatistical treatment and integration of different geological, geophysical and geochemical data. The aim is to obtain an interpretation of the region in terms of both regional geological features and modelling of local features of relevance for the mineral resource assessment. This paper presents an account of the field work and some of the new data.
Kimberlites and other ultramafic alkaline rocks in the Sisimiut–Kangerlussuaq region, southern West Greenland
The alkaline province of southern West Greenland includes swarms of dykes described as kimberlites and lamproites (Larsen 1991), and these rock types are widely distributed in the Sisimiut–Sarfartoq–Kangerlussuaq region (Figs 1, 2). Kimberlites and lamproites are potential carriers of diamond, and since the description of the Sarfartoq carbonatite complex and the kimberlitic dykes related to this complex (Larsen 1980; Secher & Larsen 1980), the Sisimiut–Sarfartoq–Kangerlussuaq region has seen several campaigns of commercial diamond exploration. The latest and most persistent stage of exploration began in the mid-1990s and has continued to date, with varying intensity. Numerous reports of diamond-favourable indicator minerals from till sampling, finds of kimberlitic dykes, and recovery of actual diamonds from kimberlitic rocks have emerged since 1995 (Olsen et al. 1999). A drilling programme in late 2001 confirmed the unusually great length and width of a magnetic kimberlitic dyke (Ferguson 2001).
Aeromagnetic survey in central West Greenland: project Aeromag 2001
The series of government-funded geophysical surveys in Greenland was continued during the spring and summer of 2001 with a regional aeromagnetic survey north of Uummannaq, project Aeromag 2001 (Fig. 1). The survey added about 70 000 line kilometres of high-quality magnetic measurements to the existing database of modern airborne geophysical data from Greenland. This database includes both regional high-resolution aeromagnetic surveys and detailed surveys with combined electromagnetic and magnetic airborne measurements.High-quality magnetic data are now available for all the ice-free area of West and South Greenland from the southern tip of Greenland to Upernavik Kujalleq/Søndre Upernavik (Fig. 1). The total surveyed area with highresolution magnetic data is 250 000 km2 and corresponds to a total of 515 000 line kilometres. Detailed surveys with combined electromagnetic and magnetic measurements were carried out in six separate surveys in selected areas of high mineral potential during project AEM Greenland 1994–1998, a total of 75 000 line kilometres. Descriptions of the previous surveys can be found in Thorning (1993), Stemp & Thorning (1995), Thorning & Stemp (1996, 1998), Stemp (1997), Rasmussen & Thorning (1999), Rasmussen & van Gool (2000) and Rasmussen et al. (2001).
Tsunami-generating rock fall and landslide on the south coast of Nuussuaq, central West Greenland
During the afternoon of 21 November 2000 the village of Saqqaq in central West Greenland was hit by a series of giant waves. Ten small boats were destroyed, but luckily neither humans nor dogs were killed. The following day a police inspection by helicopter revealed that the giant waves were caused by a major landslide at Paatuut, c. 40 km north-west of Saqqaq on the south coast of Nuussuaq (Figs 1, 2). The landslide deposits were dark grey-brown in colour, in marked contrast to the snow-covered slopes, and protruded as a lobe into the Vaigat strait. Along the adjacent coastlines the snow had been washed off up to altitudes about 50 m a.s.l. and severe damage had been caused at the abandoned coal-mining town Qullissat on the opposite side of Vaigat.
Petroleum geological activities in West Greenland in 2001
Greenland petroleum geological activities at the Geological Survey of Denmark and Greenland (GEUS) during 2001 were focused mainly on the preparation of the 2002 licensing round offshore West Greenland. Promotion of the exploration opportunities in the licensing round area between 63° and 68°N has played an important role together with launching of new seismic and geological projects. Critical evaluation of the results from the Qulleq-1 well drilled in 2000 has continued in this context. The Statoil group relinquished the eastern subarea of the Fylla licence at the end of April 2000, making all the Qulleq-1 data available for promotion purposes (see Christiansen et al. 2001a). The entire remaining area was relinquished by the end of the year. However, as part of outstanding working commitments, the Statoil group acquired approximately 1000 km of new seismic data, mainly from the western part of the licence area. These data have proven to be of great interest for companies evaluating West Greenland. The Phillips group relinquished the entire Sisimiut-West licence area by the end of the year, without entering the next phase of exploration which called for a firm commitment well.
A multidisciplinary study of the Palaeogene succession offshore southern West Greenland
A project with the aim of amalgamating an interpretation of reflection seismic data from offshore southern West Greenland with a new interpretation of well data was finalised at the Geological Survey of Denmark and Greenland (GEUS) in 2001 (Chalmers et al. 2001b). As part of this study, seismic and depositional sequences between major regional unconformities of Danian and mid-Eocene age were delineated and dated. New palaeoenvironmental and sedimentological interpretations using dinoflagellate cyst, microfossil and nannoplankton stratigraphies and palaeoenvironmental interpretations from the five exploration wells drilled offshore West Greenland in the 1970s have been combined with a revised interpretation of lithology and correlated with the aid of seismic stratigraphy. The Qulleq-1 well drilled in 2000 was relinquished late in the project period (Christiansen et al. 2002, this volume), and it has therefore only been possible to incorporate biostratigraphic information from this well into the project.
Evidence for continental crust in the offshore Palaeogene volcanic province, central West Greenland
The Palaeogene volcanic province of central West Greenland extends for 550 km from north to south and 200 km from east to west (Henderson 1973; Henderson et al. 1981; Whittaker 1996). In a preliminary interpretation of the area offshore Disko and Nuussuaq, based on older seismic data, Whittaker (1996) described a number of large rotated fault blocks containing structural closures at top volcanic level that could indicate leads capable of trapping hydrocarbons. This work, combined with the discovery of oil in the basalts onshore, led the Geological Survey of Denmark and Greenland (GEUS) to acquire 1960 km of multi-channel 2D seismic data in the area between 68°N and 71°N in 1995 (Fig. 1). These seismic data are the primary data source for the interpretation presented in this paper.
The post-basaltic Palaeogene and Neogene sediments at Kap Dalton and Savoia Halvø, East Greenland
The Palaeogene flood basalts in East Greenland are part of the North Atlantic Igneous Province (NAIP) formed during continental rifting and opening of the northern North Atlantic (Saunders et al. 1997). Along the Blosseville Kyst in southern and central East Greenland the basalts are exposed onshore from Kangerlussuaq in the south to Scoresby Sund in the north (Larsen et al. 1989). The base of the volcanic succession is exposed at Kangerlussuaq and at Savoia Halvø whereas post-basaltic sediments are found at two isolated localities, Kap Dalton and Savoia Halvø (Fig. 2). These three outcrop areas are thus key sources for biostratigraphic data to constrain the onset and duration of the Palaeogene volcanism in East Greenland, and are widely used in reconstructions of the North Atlantic region during continental break-up (e.g. Clift et al. 1998; Dam et al. 1999). In August 2001 the Geological Survey of Denmark and Greenland (GEUS) carried out field work in the sedimentary successions at Kap Dalton and Savoia Halvø. This was the first visit by geologists to Kap Dalton since 1975, and it is expected that the new data will provide important new biostratigraphic information and help to refine models for the Palaeogene of the North Atlantic. This report, and the palynological study of the sediments immediately below the basalts at Savoia Halvø presented by Nøhr-Hansen & Piasecki (2002, this volume), present the preliminary results of the field work.
Paleocene sub-basaltic sediments on Savoia Halvø, East Greenland
Field work by the Geological Survey of Denmark and Greenland (GEUS) on Savoia Halvø, central East Greenland in 2001 (see also Larsen et al. 2002, this volume) included a study of sediments underlying the Palaeogene basalts on the south coast of Scoresby Sund (Fig. 1). The importance of this small exposure is based on the fact that it provides one of the few opportunities for establishing a marine biostratigraphic date for the sediments below the basalts. Dinoflagellate cysts from the sediments provide a maximum Early Paleocene age for the onset of the volcanism in central East Greenland. Reports from previous field work have mentioned the sediments (Hassan 1953; Birkenmajer 1972), but no precise age assignment was presented due to the absence of diagnostic fossils. The sub-volcanic sediments of Savoia Halvø represent the youngest preserved marine sedimentary deposits of the Upper Palaeozoic – Cenozoic rift-basins onshore East Greenland. The overlying Palaeogene flood basalts occasionally contain very thin sedimentary beds between the lava flows, but these were deposited above sea level. Neogene uplift of the East Greenland margin brought a definitive end to accumulation in the old sedimentary basins (Watt et al. 1986; Christiansen et al. 1992).
Lower–Middle Ordovician stratigraphy of North-East Greenland
The Upper Proterozoic (Riphean) to Lower Palaeozoic succession in North-East Greenland is exposed in a broad N–S-trending belt in the fjord region between 71°38´ and 74°25´N (Fig. 1). The succession comprises mainly marine sediments accumulated during the later stages of the break-up of the Rodinia supercontinent, the subsequent opening of the Iapetus Ocean and formation of the passive margin along the edge of the Laurentian palaeocontinent. Investigations of the sedimentary succession were initiated on Ella Ø in the summer of 2000 as part of a project to investigate the development of the Laurentian margin facing the Iapetus Ocean in the Early Palaeozoic, when studies of the uppermost formations of the Riphean Eleonore Bay Supergroup to the Lower Ordovician Antiklinalbugt Formation on Ella Ø were undertaken (Stouge et al. 2001). Ella Ø was revisited during the summer of 2001, with the focus on the Ordovician formations. In addition, investigations were undertaken in the Albert Heim Bjerge area where the uppermost part of the Ordovician succession is preserved (Fig. 1).
Late Permian carbonate concretions in the marine siliciclastic sediments of the Ravnefjeld Formation, East Greenland
This investigation of carbonate concretions from the Late Permian Ravnefjeld Formation in East Greenland forms part of the multi-disciplinary research project Resources of the sedimentary basins of North and East Greenland (TUPOLAR; Stemmerik et al. 1996, 1999). The TUPOLAR project focuses on investigations and evaluation of potential hydrocarbon and mineral resources of the Upper Permian – Mesozoic sedimentary basins. In this context, the Upper Permian Ravnefjeld Formation occupies a pivotal position because it contains local mineralisations and has source rock potential for hydrocarbons adjacent to potential carbonate reservoir rocks of the partly time-equivalent Wegener Halvø Formation (Harpøth et al. 1986; Surlyk et al. 1986; Stemmerik et al. 1998; Pedersen & Stendal 2000). A better understanding of the sedimentary facies and diagenesis of the Ravnefjeld Formation is therefore crucial for an evaluation of the economic potential of East Greenland.
Qaanaaq 2001: mineral exploration reconnaissance in North-West Greenland
Project Qaanaaq 2001, involving one season’s field work, was set up to investigate the mineral occurrences and potential of North-West Greenland between Olrik Fjord and Kap Alexander (77°10´N – 78°10´N; Fig. 1). Organised by the Geological Survey of Denmark and Greenland (GEUS) and the Bureau of Minerals and Petroleum (BMP), Government of Greenland, the project is mainly funded by the latter and has the overall goal of attracting the interest of the mining industry to the region. The investigated region – herein referred to as the Qaanaaq region – comprises 4300 km2 of ice-free land centred on Qaanaaq, the administrative capital of Qaanaap (Thule) municipality. Much of the region is characterised by a 500–800 m high plateau capped by local ice caps and intersected by fjords and glaciers. High dissected terrain occurs in Northumberland Ø and in the hinterland of Prudhoe Land where nunataks are common along the margin of the Inland Ice.
Lake-catchment interactions with climate in the low Arctic of southern West Greenland
Arctic hydrology plays a central role in the earth’s heat balance and ocean circulation (Vörösmarty et al. 2001). Future changes associated with human influence on the climate system are also predicted to cause major changes in the energy and hydrologic mass balance of Arctic catchments. Climate change will likely affect permafrost and snowmelt, which dominate Arctic hydrology and control the chemistry of surface runoff (and hence streams and lakes) as water percolates through the active layer. However, the controls and dynamic impact of snowmelt are poorly understood, because this critical timeframe is often missed by sampling programmes. In the Søndre Strømfjord area only the broadest aspects of hydrologic variability have so far been documented (Hasholt & Søgaard 1976).
Glaciological investigations on ice-sheet response in South Greenland
The reaction of the world’s large ice sheets to global climate change is still in the focus of scientific debate. Recent investigations have shown pronounced thinning in the southern part of the Greenland ice sheet (Inland Ice). In order to investigate the cause of the observed thinning and to judge the sensitivity of this part of the ice sheet a combined field work, remote sensing and modelling project was designed. A glaciological transect was established in May 2001 on one of the main outlet glaciers in South Greenland (Fig. 1), and the first data are now available. In addition, the history of the glacier variations during the last 40 years has been reconstructed.
Scientific publications on Greenland by the Survey, 2001
Field activities in Greenland by the Geological Survey of Denmark and Greenland (GEUS) in 2001 were again many and varied. They included economic investigations of crystalline basement and sedimentary rocks in North-West Greenland, and a systematic mapping project combined with resource evaluation in the boundary zone of the Nagssugtoqidian and Rinkian mobile belts of central and southern West Greenland. In addition, studies of the Vendian to Lower Palaeozoic successions in North-East Greenland and of the Palaeogene sediments of central East Greenland were carried out, a major aeromagnetic survey was flown in central West Greenland, and investigations of Holocene lake sediments in southern West Greenland were continued.
Cambrian shelf stratigraphy of North Greenland
The Lower Palaeozoic Franklinian Basin is extensively exposed in northern Greenland and the Canadian Arctic Islands. For much of the early Palaeozoic, the basin consisted of a southern shelf, bordering the craton, and a northern deep-water trough; the boundary between the shelf and the trough shifted southwards with time. In North Greenland, the evolution of the shelf during the Cambrian is recorded by the Skagen Group, the Portfjeld and Buen Formations and the Brønlund Fjord, Tavsens Iskappe and Ryder Gletscher Groups; the lithostratigraphy of these last three groups forms the main focus of this paper. The Skagen Group, a mixed carbonate-siliciclastic shelf succession of earliest Cambrian age was deposited prior to the development of a deep-water trough. The succeeding Portfjeld Formation represents an extensive shallow-water carbonate platform that covered much of the shelf; marked differentiation of the shelf and trough occurred at this time. Following exposure and karstification of this platform, the shelf was progressively transgressed and the siliciclastics of the Buen Formation were deposited. From the late Early Cambrian to the Early Ordovician, the shelf showed a terraced profile, with a flat-topped shallow-water carbonate platform in the south passing northwards via a carbonate slope apron into a deeper-water outer shelf region. The evolution of this platform and outer shelf system is recorded by the Brønlund Fjord, Tavsens Iskappe and Ryder Gletscher Groups. The dolomites, limestones and subordinate siliciclastics of the Brønlund Fjord and Tavsens Iskappe Groups represent platform margin to deep outer shelf environments. These groups are recognised in three discrete outcrop belts - the southern, northern and eastern outcrop belts. In the southern outcrop belt, from Warming Land to south-east Peary Land, the Brønlund Fjord Group (Lower-Middle Cambrian) is subdivided into eight formations while the Tavsens Iskappe Group (Middle Cambrian - lowermost Ordovician) comprises six formations. In the northern outcrop belt, from northern Nyeboe Land to north-west Peary Land, the Brønlund Fjord Group consists of two formations both defined in the southern outcrop belt, whereas a single formation makes up the Tavsens Iskappe Group. In the eastern outcrop area, a highly faulted terrane in north-east Peary Land, a dolomite-sandstone succession is referred to two formations of the Brønlund Fjord Group. The Ryder Gletscher Group is a thick succession of shallow-water, platform interior carbonates and siliciclastics that extends throughout North Greenland and ranges in age from latest Early Cambrian to Middle Ordovician. The Cambrian portion of this group between Warming Land and south-west Peary Land is formally subdivided into four formations.The Lower Palaeozoic Franklinian Basin is extensively exposed in northern Greenland and the Canadian Arctic Islands. For much of the early Palaeozoic, the basin consisted of a southern shelf, bordering the craton, and a northern deep-water trough; the boundary between the shelf and the trough shifted southwards with time. In North Greenland, the evolution of the shelf during the Cambrian is recorded by the Skagen Group, the Portfjeld and Buen Formations and the Brønlund Fjord, Tavsens Iskappe and Ryder Gletscher Groups; the lithostratigraphy of these last three groups forms the main focus of this paper. The Skagen Group, a mixed carbonate-siliciclastic shelf succession of earliest Cambrian age was deposited prior to the development of a deep-water trough. The succeeding Portfjeld Formation represents an extensive shallow-water carbonate platform that covered much of the shelf; marked differentiation of the shelf and trough occurred at this time. Following exposure and karstification of this platform, the shelf was progressively transgressed and the siliciclastics of the Buen Formation were deposited. From the late Early Cambrian to the Early Ordovician, the shelf showed a terraced profile, with a flat-topped shallow-water carbonate platform in the south passing northwards via a carbonate slope apron into a deeper-water outer shelf region. The evolution of this platform and outer shelf system is recorded by the Brønlund Fjord, Tavsens Iskappe and Ryder Gletscher Groups. The dolomites, limestones and subordinate siliciclastics of the Brønlund Fjord and Tavsens Iskappe Groups represent platform margin to deep outer shelf environments. These groups are recognised in three discrete outcrop belts - the southern, northern and eastern outcrop belts. In the southern outcrop belt, from Warming Land to south-east Peary Land, the Brønlund Fjord Group (Lower-Middle Cambrian) is subdivided into eight formations while the Tavsens Iskappe Group (Middle Cambrian - lowermost Ordovician) comprises six formations. In the northern outcrop belt, from northern Nyeboe Land to north-west Peary Land, the Brønlund Fjord Group consists of two formations both defined in the southern outcrop belt, whereas a single formation makes up the Tavsens Iskappe Group. In the eastern outcrop area, a highly faulted terrane in north-east Peary Land, a dolomite-sandstone succession is referred to two formations of the Brønlund Fjord Group. The Ryder Gletscher Group is a thick succession of shallow-water, platform interior carbonates and siliciclastics that extends throughout North Greenland and ranges in age from latest Early Cambrian to Middle Ordovician. The Cambrian portion of this group between Warming Land and south-west Peary Land is formally subdivided into four formations.
Petroleum geological activities onshore West Greenland in 1996, and drilling of a deep exploration well
The 1996 summer season saw continued petroleum geological activities in the Disko–Nuussuaq area, onshore West Greenland. These took the form of a geological field project led by the Geological Survey of Denmark and Greenland (GEUS), and continued commercial exploration by grønArctic Energy Inc. (grønArctic). In the second year of their licence, grønArctic carried out an airborne geophysical programme early in 1996 and drilled a c. 3 km deep exploration well on Nuussuaq, GRO#3, in the late summer (Fig. 1). Although the detailed results from grønArctic’s exploration are confidential (apart from the information made available at conferences and in press releases), it is evident that knowledge of the Nuussuaq Basin has greatly increased in recent years and that the basin has considerable exploration potential of its own (see Christiansen et al., 1995b, 1996a). The activities by GEUS and the exploration by grønArctic will significantly improve the understanding of the petroleum system of the basin; available data from the 1996 activities have shed light on the types and distribution of oils, source rocks and potential reservoir units.
Petroleum geological investigations in East Greenland: project ‘Resources of the sedimentary basins of North and East Greenland’
The multidisciplinary research project ‘Resources of the sedimentary basins of North and East Greenland’ was initiated in 1995 with financial support from the Danish Research Councils (Stemmerik et al., 1996). In 1996, the hydrocarbon-related studies focused on the sedimentary basins in East Greenland between latitudes 71°N and 74°N (Fig. 1) where nine field teams worked for six weeks in July and August supported by a Hughes 500 helicopter. Within the framework of the project, additional hydrocarbon-related field studies were undertaken in 1996 in western North Greenland, and ore-geological studies were carried out in much of North Greenland (Kragh et al., 1997; Stemmerik et al., 1997). The 1996 field work in East Greenland concentrated on integrated structural, sedimentological and biostratigraphical studies of the Upper Permian and Mesozoic successions. Two Ph.D. projects focused on the sedimentology of the Lower Triassic Wordie Creek Formation and the diagenesis of the Middle and Upper Jurassic succession. Post-doctorate studies were carried out on the Mesozoic–Tertiary structural development of the basin and the mineralisation of the Upper Permian Ravnefjeld Formation. Three student projects on Lower Triassic and Middle Jurassic ammonite stratigraphy, Upper Permian sedimentology, and fault-associated mineralisation were also included in the work. The most important new results arising from the 1996 field work are: 1) Re-interpretation of the Upper Permian Schuchert Dal Formation as a lowstand turbidite unit within the Ravnefjeld Formation; 2) Recognition of Middle Jurassic deposits and thick lowermost Cretaceous sandstones on Hold with Hope; 3) Interpretation of a full spectrum of scarp-derived coarse-clastic mass movement deposits interbedded with Cretaceous shales on eastern Traill Ø; 4) The presence of a thick sand-rich Cretaceous turbidite succession on eastern Traill Ø; 5) Re-interpretation of the Mesozoic–Cenozoic fault systems on Traill Ø and Geographical Society Ø.
Mafic igneous rocks and mineralisation in the Palaeoproterozoic Ketilidian orogen, South-East Greenland: project SUPRASYD 1996
The multidisciplinary SUPRASYD project (1992–96) focused on a regional investigation of the Palaeoproterozoic Ketilidian orogenic belt which crosses the southern tip of Greenland. Apart from a broad range of geological and structural studies (Nielsen et al., 1993; Garde & Schønwandt, 1994, 1995; Garde et al., 1997), the project included a mineral resource evaluation of the supracrustal sequences associated with the Ketilidian orogen (e.g. Mosher, 1995). The Ketilidian orogen of southern Greenland can be divided from north-west to south-east into: (1) a border zone in which the crystalline rocks of the Archaean craton are unconformably overlain by Ketilidian supracrustal rocks; (2) a major polyphase pluton, referred to as the Julianehåb batholith; and (3) extensive areas of Ketilidian supracrustal rocks, divided into psammitic and pelitic rocks with subordinate interstratified mafic volcanic rocks (Fig. 1). The Julianehåb batholith is viewed as emplaced in a magmatic arc setting; the supracrustal sequences south of the batholith have been interpreted as either (1) deposited in an intra-arc and fore-arc basin (Chadwick & Garde, 1996), or (2) deposited in a back-arc or intra-arc setting (Stendal & Swager, 1995; Swager, 1995). Both possibilities are plausible and infer subduction-related processes. Regional compilations of geological, geochemical and geophysical data for southern Greenland have been presented by Thorning et al. (1994). Mosher (1995) has recently reviewed the mineral exploration potential of the region. The commercial company Nunaoil A/S has been engaged in gold prospecting in South Greenland since 1990 (e.g. Gowen et al., 1993). A principal goal of the SUPRASYD project was to test the mineral potential of the Ketilidian supracrustal sequences and define the gold potential in the shear zones in the Julianehåb batholith. Previous work has substantiated a gold potential in amphibolitic rocks in the south-west coastal areas (Gowen et al., 1993.), and in the amphibolitic rocks of the Kutseq area (Swager et al., 1995). Field work in 1996 was focused on prospective gold-bearing sites in mafic rocks in South-East Greenland. Three M.Sc. students mapped showings under the supervision of the H. S., while an area on the south side of Kangerluluk fjord was mapped by H. S. and W. M. (Fig. 4).
The Nioghalvfjerdsfjorden glacier project, North-East Greenland: a study of ice sheet response to climatic change
Glaciological research was initiated in 1996 on the floating glacier tongue filling Nioghalvfjerdsfjorden in NorthEast Greenland (Fig. 1), with the aim of acquiring a better understanding of the response of the Greenland ice sheet (Inland Ice) to changing climate, and the implications for future sea level. The research is part of a three year project (1996–98) to advance research into the basic processes that contribute to changes in the ocean volume with a changing climate. Five nations are participants in the project, which is supported by the European Community (EC) Environment and Climate Programme. The Geological Survey of Denmark and Greenland (GEUS) and the Danish Polar Center are the Danish partners in the project, both with integrated research themes concentrated on and around Nioghalvfjerdsfjorden.
Palaeo-oil field in a Silurian carbonate buildup, Wulff Land, North Greenland: project ‘Resources of the sedimentary basins of North and East Greenland’
The multi-disciplinary research project ‘Resources of the sedimentary basins of North and East Greenland’ was initiated in 1995 with financial support from the Danish Research Councils (Stemmerik et al., 1996). During the 1996 field season, hydrocarbon-related studies within the project were focused on the sedimentary basins of East Greenland (Stemmerik et al., 1997), while field work in the Franklinian Basin of North Greenland from which the observations reported here derive, was limited to two weeks in early August. The project also includes research related to the ore geology of North Greenland, especially focused on the zinc-lead deposit at Citronen Fjord (Fig. 1). This aspect of the project is covered by Langdahl & Elberling (1997) and Kragh et al. (1997). The work on the Franklinian Basin succession was based at Apollo Sø in eastern Wulff Land (Fig. 1), with the main emphasis on sedimentological and sequence stratigraphic studies of carbonates of the Cambrian portion of the Ryder Gletscher Group and the Silurian Washington Land Group. These two carbonate-dominated shelf successions are equivalent in age to the main source rocks for liquid hydrocarbons in the basin, and have been suggested as potential reservoir units in the conceptual reservoir models proposed for the basin (Christiansen, 1989). Earlier investigations in the region have shown that small occurrences of bitumen are widespread in western North Greenland, although typically closely associated with nearby source rocks (Christiansen et al., 1989a). Notable exceptions are the asphalt seepages in southern Warming Land and southern Wulff Land (Fig. 1); in these cases, long distance migration of the order of 75–100 km is envisaged (Christiansen et al., 1989a). During the 1996 field season, a palaeo-oil field was identified in a carbonate buildup in eastern Wulff Land (Victoria Fjord buildup), thus demonstrating for the first time that Silurian buildups have formed large-scale reservoirs for generated hydrocarbons in the geological past.
The role of bacteria in degradation of exposed massive sulphides at Citronen Fjord, North Greenland: project ‘Resources of the sedimentary basins of North and East Greenland’
The multidisciplinary research project ‘Resources of the sedimentary basins of North and East Greenland’ was initiated in 1995 with financial support from the Danish Research Councils (Stemmerik et al., 1996). The Citronen Fjord zinc prospect (Fig. 1) discovered by Platinova A/S in 1993 is by far the largest sulphide occurrence known in North Greenland, and is currently being investigated as a potential exploitable resource. However, the mining and processing of sulphide ores can create serious pollution problems in the surrounding terrestrial and aquatic ecosystems by exposing large amounts of sulphidic material to atmospheric oxygen and ‘attack’ by mineral-oxidising bacteria. At lower latitudes, the slow abiotic oxidation of metal sulphides is known to be significantly accelerated by bacterial attack. A microbiological investigation of the Citronen Fjord zinc deposit was initiated in the summer of 1995 to investigate the role bacteria might play in oxidation of sulphidic material in High Arctic areas. This is a joint project involving the Danish Environmental Research Institute (Department of Arctic Environment) and the University of Aarhus (Department of Microbial Ecology).
Natrophosphate from the Ilímaussaq alkaline complex, South Greenland
The rare mineral natrophosphate has been identified for the first time in the Ilímaussaq alkaline complex in a drill core from the Kvanefjeld area. It occurs sparsely in zoned veinlets with cores of natrophosphate and borders of fibrous trona. The natrophosphate is more or less smoky, transparent and unaltered. The refractive index n = 1.448 ± 0.005 is low compared to that given for the material from the type locality, Khibina alkaline complex, Kola Peninsula; the unit cell parameter a = 27.76 ± 0.05 Å is in excellent agreement with that given for the material from the type locality. The veins occur in hyper-agpaitic naujakasite lujavrite; villiaumite is an associated mineral. Only a few water-soluble minerals have so far been found in the Ilímaussaq alkaline complex compared to the wealth of such minerals in the Khibina and Lovozero alkaline complexes. This is possibly at least partly due to lack of necessary precautions during sampling.
Ore geological studies of the Citronen Fjord zinc deposit, North Greenland: project ‘Resources of the sedimentary basins of North and East Greenland’
The multidisciplinary research project ‘Resources of the sedimentary basins of North and East Greenland’ was initiated in 1995 with financial support from the Danish Research Councils (Stemmerik et al., 1996). In the 1996 field season, ore geological studies continued on the shale-hosted Citronen Fjord zinc-lead prospect in North Greenland (Figs 1, 2). Platinova A/S discovered the deposit in 1993, and has subsequently explored the area by means of geological mapping, gravity surveys and diamond drilling. About 30 km of diamond drilling have been completed, and a resource of over 20 million tons of stratiform ore with 7% zinc and 1% lead has been estimated (Platinova A/S, 1996a, b). An additional fault-controlled, high-grade zinc-mineralised zone was encountered in the north-western part of the ‘Discovery Zone’ in 1996 (Platinova A/S, 1996b).
Seismic investigation of the East Greenland volcanic rifted margin
The SIGMA project (Seismic Investigation of the Greenland MArgin) was designed to make accurate measurements of crustal thickness, velocity structure and seismic reflectivity along the hotspot-influenced volcanic rifted margin (VRM) off South-East Greenland (Fig. 1). SIGMA is a joint project between researchers at Woods Hole Oceanographic Institution (Woods Hole, Mass., USA) and the Danish Lithosphere Centre (DLC), and data was acquired on a cruise with R/V Maurice Ewing in August–October 1996. VRMs are characterised by a prism of igneous rocks that occupies the continent–ocean transition zone in an 80 to 150 km wide belt, several times thicker than normal oceanic crust, and which extends in some regions for more than 1500 km along strike. This thick igneous crust has two characteristics on seismic data: a seawarddipping reflector sequence (SDRS) interpreted as subaerially erupted basalt flows and intercalated volcanoclastics, and a high-velocity lower crust with P-wave velocities (7.2–7.6 km/s) suggestive of mafic to ultramafic intrusive rocks (Hinz, 1981; Mutter et al., 1982, 1984, 1988; Larsen & Jakobsdóttir, 1988; White & McKenzie, 1989; Holbrook & Kelemen, 1993). Several models for the thermal and mechanical processes involved in the formation of VRMs have been proposed, including: decompression melting during passive upwelling near a mantle plume (White & McKenzie, 1989); actively upwelling plume heads impinging on the base of the lithosphere (Richards et al., 1989; Duncan & Richards, 1991; Griffiths & Campbell, 1991); enhanced upper mantle convection driven by steep, cold lithospheric edges adjacent to the rift (Mutter et al., 1988) and hot upper mantle due to non-plume ‘hot cells’ or insulation by supercontinents (Gurnis, 1988). SIGMA consists of four transects systematically sampling the structure of the South-East Greenland margin and the continent–ocean transition at increasing distance from the Iceland hotspot track, in order to investigate the South-East Greenland VRM with respect to the following questions: 1) What is the structure of the transition from continental to thick igneous crust, and thence to normal oceanic crust? Is the transition abrupt or gradual? To what extent does faulting play a role? Does the abruptness of the continent–ocean boundary change with distance from the Iceland plume? 2) What was the total volume of magmatism during continental breakup on the South-East Greenland margin and its conjugates, and how does it vary in space and time? How does this magmatism relate to distance from the Iceland plume and to its temporal magmatic budget? What is the proportion of plutonic to volcanic rocks, and how does this vary with distance from the hotspot track and with total crustal thickness? 3) Does high velocity lower crust exist beneath the margin, and if so, is there any evidence that its composition, thickness, and distribution change along strike? How might such changes relate to variations in melting conditions (temperature and degree of melting) with distance from the plume? 4) Is the structure of the South-East Greenland margin symmetrical with its conjugate margins on the Hatton–Rockall Bank and Iceland–Faeroes Ridge? What combinations of pure shear and simple shear processes might explain the conjugate structures?