bluuebunny/crossref_metadata_2025 huggingface dataset:
Geological investigations of the Igaliko dyke swarm, South Greenland
Authors: Pearce N.J.G , Emeleus C.H
Published: June 2021

Field work in 1984 in the Motzfeldt area included an investigation of the Gardar dyke swarm in this area. The dyke swarm was examined at the folIowing places in or near the Igaliko Complex: north of Motzfeldt Sø, north af Gieseckes Dal, Igaliko, Flinks Dal, Mellemlandet, in 0stfjordsdal (north-west side), and west of Narssarssuaq river. Except at Østfjordsdal, the dykes resemble assemblages found elsewhere in the TugtutoqIlimaussaq-Igaliko swarm. Porphyritic and non-porphyritic trachytes and phonolites (the latter less common), basalts and dolerites, lamprophyres, big feldspar dolerites and carbo- natites are all present. The latter are much more abundant than previously recognised, and are occasionally of considerable length. The relative proportions vary; basaltic and doleritic dykes are particularly abundant towards the centre of the swarm, Le. west of Narssarssuaq river where dilation due to dykes is greatest, at about 10 per cent; elsewhere values of 3-4 per cent were obtained.
Ketilidian uranium mineral occurrences in South Greenland
Authors: Armour-Brown A , Wallin B
Published: June 2021

The Sydex project is financed by the Ministry of Energy's Research Programme 1984 in order to evaluate the uranium mineral occurrences found during the earlier reconnaissance project, Syduran. The main objectives of the field season were: (1) to map and sample in detail the uranium occurrence at Igdlorssuit (fig. 20) in the Migmatite Complex which was found in 1982 (Armour-Brown et al., 1984), so as to evaluate its economic potential and place it in its geological setting, (2) to locate the source of a high gamma-spectrometer anomaly on the nunatak north of Nordre Sermilik in the Granite Zone, and to map the surrounding geology.
The North Greenland fold belt in eastern Nansen Land
Authors: Friderichsen J.D , Bengaard H.-J
Published: June 2021

Field work in 1984 shows that Nansen Land consists of clastic rocks of the carbonaceous Paradisfjeld Group and terrigeneous rocks of the Polkorridoren Group; both are lower Cambrian in age and deposited in a slope and fan environment. Two major Ellesmerian (Devonian to Carboniferous) phases of deformation gave rise to east-west trending folds and schistosities. Three phases of Eurekan (upper Cretaceous to Tertiary) deformation, associated with dyke intrusion, are recognised. The second of these may be related to transpression on the Harder Fjord fault zone, though no major strike-slip movement seems to have taken place.
Cambrian - Lower Silurian slope and basin stratigraphy between northern Nyeboe Land and western Amundsen Land, North Greenland
Authors: Higgins A.K , Soper N.J
Published: June 2021

Brief description is given of the Cambrian - Lower Silurian sequence in northern parts of central and western North Greenland, which underlies the turbidites of the Silurian Peary Land Group. Lower parts of the sequence pertain to the southern shelf, and upper parts to the northern slope or basin.
Reconnaissance scale geochemical survey in central and western North Greenland Preliminary results concerning zinc and barium
Authors: Steenfelt A
Published: June 2021

Stream sediment samples were colleeted at a density of 1 sample per 30 km2 in Warming Land, Wulff Land, Nares Land, Nansen Land and along Navarana Fjord. The minus 0.1 mm grain size fraetion of the samples was analysed by X-ray fluorescenee for 30 elements. The regional distribution pattem for the contents of Zn and Ba reflects the lithological changes. Lowest values for both elements occur in the lower Palaeozoic earbonate platform and the contents gradually inerease northwards in the flysch deposits of the Silurian basin to a high level for both elements in samples from the folded Cambrian basin deposits in Nansen Land. Anomalously high values of Zn and Ba at Navarana Fjord and at north-west Nares Land are associated with a thin Cambro-Ordovician unit of blaek dolomitie mudstones. Reeonnaissanee zine anomalies and the occurrenee of massive sphalerite in the matrix of a breccia zone at Navarana Fjord are taken as indications of a major zine mineralising event.
Gardar dykes north of the Igaliko Syenite Complex, southern Greenland
Authors: Upton B.G.J , Fitton J.G
Published: June 2021

An ENE-WSW trending swarm of Gardar dykes, traversing Mellemlandet and G. E Holm Nunataq is principally composed of a 'main series' with compositions ranging from alkali olivine basalt to trachyte and rhyolite, and scarcer phonolitic trachyte associates. The most basic 'main series' magmas were emplaced as several giant dykes up to 650 m wide. Synformally layered gabbroic and anorthositic cumulates are locally developed within these. At Syenitknold internal differentiation within a giant dyke gave rise to syenogabbros, layered syenite cumulates and peralkaline nepheline syenite pegmatites. A large xenolithic mass of exotic feldspathic gabbro within the syenites is ascribed to the foundering of feldspar-rich roofing facies into the underlying magma chamber. Less extreme differentiation in the same giant dyke east of Syenitknold produced syenogabbroic cumulates containing evidence for vigorous convective flow having developed in the cooling intrusion. Smaller (< 40 m wide) and younger dykes are almost invariably of more differentiated character. The commonest dykes ( < 15 m wide) are of benmoreite and trachyte. Dykes with their interiors crowded with plagioclase xenocrysts and anorthositic inclusions are referred to as 'big feldspar dykes' (B.F.D.s). While all compositions from basalt to benmoreite may be involved in the B.F.D.s, the B.F.D. character is typical of the hawaiites and mugearites. Small (typically < 1 m), scarce dykes and sills of highly silica-undersaturated types range from ultramafic lamprophyres to carbonatites. These may be representative of a compositional continuum between 36 and 2 wt % SiO2,. The main swarm is so closely similar to that seen to the WSW, extending through Tugtutoq and the Narssaq and Qagssiarssuk areas, that it is thought to be merelya faulted continuation ofthe latter. Itso, this swarm, c. 15 km across, is at least 140 km long. The magnitude and extent of this alkaline swarm and its individual components, may well be unique: it differs from other swarms (e.g. that of the roughly contemporaneous Nunarssuit-Isortoq swarm) in the size and abundance of the salic dykes within it. It was almost certainly related to extensive fissure eruption of basic to salic lavas. A clockwise change of several degrees between the orientation of early giant dykes and later differentiated dykes is related to a change in the extensional stress direction during the development of the Gardar rift system.
The development of thin thrust sheets and basement-cover sandwiches in the southern part of the Rinkian belt, Umanak district, West Greenland
Authors: Pulvertaft T.C.R
Published: June 2021

At the southern margin of the Rinkian belt, West Greenland, it can be demonstrated that the Lower Proterozoic Marmorilik Marble Formation, which was deposited unconformably on a gneiss basement, has been squeezed and stretched into a thin recumbent syneline and overridden by the basement over an area of more than 1000 km2. Aseeond supracrustal cover unit, seen now as a thin mylonitic biotite schist horizon, occurs at a slightly higher structural level, and marks the site of another thrust along which the gneiss basement has overridden its supracrustal cover. The demonstration that a superficially simple sequence consisting of concordant layers of different gneiss types and supracrustal rocks is in faet a pile ofthrust sheets, has important implications for the interpretation of both West Greenland and other Precambrian areas.
A decade of glacier investigations for utilisation of Greenland hydropower
Authors: Weidick A , Thomsen H.H
Published: June 2021

Over the past decade GGU has colIected basic glaciological, climatic and hydrological data from the basins that are potential suppliers of hydropower in West Greenland. Detailed topographic maps of the margins of the lnland Ice near Frederikshåb and Jakobshavn have been used to record changes in the drainage pattern due to changing positions of the ice margin. Landsat images are used to augment the field data, particularly using scenes recorded late in the melting season under low sun angles. Computer processing of the Landsat data enhances individual elements that are otherwise not clearly discernable. Since ice-dammed lakes can form natural reservoirs they have been closely studied with a view to controlling the periodic catastrophic outbursts. Statisticai modeIling has been used extensively utilising long series of meteorological data from coastaIstations to simulate the mass balance and mnoff patterns on the margin of the lnland lce.
Completion of field work for the 1:500 000 mapping and regional geological studies in central and western North Greenland
Authors: Henriksen N
Published: June 2021

Field activities comprising the second, and final season of the systematic field mapping programme in central and western North Greenland were carried out from June to August 1985. The field investigations were concluded for the 1:500000 map sheet of the area between J. P. Koch Fjord (c. 400 W), in the east, and north-easternmost Washington Land (65°W) in the west; the southern boundary of the map sheet is 81°N (fig. 1). General geological investigations forrned an integral part of the mapping programme. A special source rock project, financed by the Danish Ministry of Energy, was fully integrated with the mapping programme (Christiansen et al., this report). As in 1984 a tent base camp in south-eastern Warming Land served as an operation centre for the expedition. Two chartered Jet Ranger helicopters and a Twin Otter aircraft were based here, and served the expedition groups with transport facilities throughout the season. Mobilisation and demobilisation of the expedition from Denmark were carried out with help from the Royal Danish Air Force, who airlifted the expedition to and from the Canadian Forces Station (CFS) Alert in north-east Ellesmere Island, Canada. Personnel, equipment and fuel were flown into the base camp from Alert with the Twin Otter. The expedition group numbered 40, comprising 12 two-man geological parties, a fourman drilling team and 12 supporting personnel, including aircraft crew members. As in 1984, the operation area extended about 500 km from east to west, and 150-200 km from south to north. The 12 geological teams and the drilling team utilised about 130 camp sites. At the end of the 1985 season, the temporary huts and tents at base camp were dismantled and, together with all the equipment, were taken back to Denmark. Fuel depots and equipment in other parts of the working area, which is part of the North and East Greenland National Park, were also removed.
Indication of migrated hydrocarbons in Tertiary volcanic rocks from western Nûgssuaq, central West Greenland
Authors: Pedersen A.K
Published: June 2021

During the field season of 1985 the author briefly visited Marrait kitdlit at the southern part of the entrance to the Itivdle valley on Nugssuaq (fig. 1). This paper briefly describes the occurrence of possibly migrated organic material in a vein in Tertiary basalt and presents it in a regional context.
On the occurrence of scheelite in the Archaean Malene supracrustal rocks, southern West Greenland
Authors: Appel P.W.U , Garde A A
Published: June 2021

Scheelite in the Godthåbsfjord area (fig. 1) was found in heavy mineral concentrates from stream sediments in 1982, and in situ scheelite was discovered in 1982 on Storø in Godthåbsfjord (Appel, 1983a). During 1983 further work was carried out on the islands of Storø and Sermitsiaq in Godthåbsfjord and on the Store Malene mountain next to Nuuk (Godthåb), as aresult of which several scheelite-bearing horizons were found (Appel, 1984). During 1985 a detailed mapping programme was carried out on Store Malene by A. A. Garde. Subsequently, exposures on Store Malene as well as the island of Simiutat south of Nuuk were investigated by ultra-violet light. A similar survey has oeen carried out by Olsen (this volume) on the island of Sermitsiaq. Thc folIowing report is mainly based on field observations combined with investigation of a few thin sections. Laboratory work has been confined to X-ray identification of scheelite in four samples from Store Malene and one sample from Simiútat.
Fourth year of glaciological field work at Tasersiaq and Qapiarfiup sermia, West Greenland
Authors: Olesen O.B
Published: June 2021

As part of the GGU programme for the regional mapping of the hydroelectric potential of West Greenland, glaciological and climatological investigations were continued at 'Amitsuloq' ice cap in 1985, while only glaciological measurements were made at Qapiarfiup sermia. The field programme at Qapiarfiup sermia was originally started in March 1981, whereas the permanent fieId station near 'Amitsuloq' ice cap (fig. 1) was first established in August of the same year. Briefreports of the work have been given by Olesen (1982), Olesen & Andreasen (1983), and Olesen (1985).
Systematic geological mapping in 1985 in central and western North Greenland General introduction to the present collection of papers
Authors: Henriksen N
Published: June 2021

The fifth and final field season in GGU's North Greenland programme (1978-80, 1984-85) comprised geological mapping and general geological investigations in the region between J. P. Koch Fjord (400 W) and Washington Land (65°W), the same area as the 1984 investigations. A working party of 40 participants, consisting of 12 geological two-man teams, a four-man drilling team and 12 supporting personnel, including aircraft crews, worked in the region for two months during the summer. The preliminary results of the geological work are presented in in this report.
The buried western extension of the Navarana Fjord escarpment in central and western North Greenland
Authors: Escher J.C , Larsen P.-H
Published: June 2021

Three lines of argument are presented in support of the existence and location of a presumed western buried extension of the Navarana Fjord escarpment: (1) comparison between sediment thickness of two adjacent sections on either side of the escarpment; (2) the occurrence of limestone boulder conglomerates at the base of the Merqujôq Formation; (3) abrupt changes in deformation style and intensity across the region controlled by the escarpment.
Magnetic susceptibility and palaeomagnetic collection of rocks from central and western North Greenland
Authors: Abrahamsen N , Van der Voo R
Published: June 2021

Some 1900 orientated palaeomagnetic samples were collected from 372 sites in central and western North Greenland in 1985 covering the complete rock sequence from the Precambrian crystalline basement to the Upper Cretaceous dolerite dykes. More than 1100 susceptibility measurements from 91 sites were measured in situ on as many rock units as possibie with susceptibilities above 10-4 SI units. The susceptibilities in the region span 4 orders of magnitude, but the geometrical mean values of major rock groups are well clustered and well defined suggesting that indirect subsurface mapping by aeromagnetic surveying may be a feasible tool for future investigations.
Review of the Survey's activities in 1986
Authors: Ghisler M
Published: June 2021

The Geological Survey of Greenland (GGU) continued in 1986 the systematic investigation of the geology of Greenland. The work comprises geological mapping and basic research as well as applied geology and geophysics (fig. 1). The long term purpose is to establish the necessary geological background for evaluation of the potential of the non-living resources. The scientific and technical staff of 112 based in Copenhagen and 87 participating in the field work in Greenland carried out programmes of geological mapping and investigation, glaciological investigations, and mineral and oil assessments which included geochemical and geophysical methods. In April 1986 GGU celebrated its 40th anniversary. A special publication dedicated to GGU's former director, K. Ellitsgaard-Rasmussen, was issued which covers different aspects of the Survey's work in the developments in Greenland geology over the past ten years.
Geophysical investigations of the Qaqarssuk Carbonatite Complex, southern West Greenland
Authors: Kjærgaard M , Knudsen C , Abrahamsen N
Published: June 2021

During the summers of 1984 and 1985, geophysical investigations were made in the Qaqarssuk area, situated 65°23'N, 51°40'W, in connection with exploration for phosphorus, niobium and lanthanide deposits of potential economic interest. The geophysical field work carried out in the summer of 1984 has previously been briefly discussed (Kjærgaard & Olsen, 1985a). Most of the interpretations have now been completed, some of which are presented below, together with the new results from 1985. The investigations focussed on three subjects: (1) Shallow seismic and geoelectric measurements to map the thickness of residual soil (possibly enriched in P and Nb) overlying the carbonatite. (2) Radiometric meaSurements to localise pyrochlore-rich (V bearing) and lanthanide-rich carbonatites (Th bearing). (3) Magnetic investigations, primarily to map the structures in the carbonatite. A general description of the geology of the complex is given in Knudsen (1985) and Knudsen (1986). A geological sketch map is shown in fig. 1.
Scheelite occurrences in granulite facies metamorphosed supracrustals, West Greenland
Authors: Appel P.W.U
Published: June 2021

In 1982 the first traces of scheelite in heavy mineral concentrates from stream sediments were found in the Godthåbsfjord area. Subsequently a quite extensive scheelite mineralisation has been found in the Malene supracrustal rocks (Appel, 1986a). During 1985 a regional stream-sediment sampling programme was carried out covering an area of about 30 000 km2 within the Godthåb area. As aresult of this programme scheelite was found in most of the streams draining Malene supracrustal rocks (Appel, 1986b). One of the areas which appeared to be interesting is the Sermilik area c. 75 km south of Nuuk. In this area several streams with high contents of scheelite were found. The area has been subject to granulite facies metamorphism and a major granitic intrusion emplaced. Both events might have caused extensive mobilisation and subsequent upgrading of stratabound scheelite mineralisation. The supracrustals are situated at the shore of a smal! fjord, where ice rarely causes problems for shipping. The alpine topography, with near vertical cliffs, poses an obstacle for prospecting. The present paper describes only field observations. Laboratory work is confined to X-ray identification of scheelite in some of the heavy mineral concentrates and in a few rock samples.
Gravity survey on ice offshore South-East Greenland
Authors: Jakobsdóttir S.S , Larsen H.C
Published: June 2021

In the early spring an effort was made to extend some lines of marine gravity data from the shelf into the coast north of Ammassalik. A net of marine gravity data covers the shelf off East Greenland, reaching from about 59°N to 74°N (fig. 1). South of Scoresby Sund the gravity data are mostly coIlected in regions floored by oceanic crust, though some of the lines cross the ocean-to-continent boundary. Between Ammassalik and Scoresby Sund the oceanto-continent transition zone (OCT) runs dose to the coast (Larsen, 1984), and is probably related to the onshore Tertiary basaltic dyke swarm described by Wager & Deer (1938) and Myers (1980) (fig. 2). An offshore continuation of the dyke swarm was proposed by Larsen (1978). The aim of the gravity project was to obtain three tie-lines connecting the offshore marine gravity data to onshore gravity data to be obtained by the Geodetic Institute during the summer of 1986 (fig. 1). Such tie-lines would provide crucial information on the gravity field over the dyke swarm and might aid in a more precise location ofthe initial line of rifting in this region. The survey area is covered with ice most of the year. Gravity surveys on ice have been carried out both in the Bothnian Bay (Lehmuskoski & Makinen, 1978) and on ice-islands in the polar pack ice (Crary et al., 1952; Kristoffersen, 1982). Thus a helicopter survey with portable gravimeter and readings on the ice was planned for the South-East Greenland survey as this would provide gravity data from the area ofinterest at lowest cost. The ice cover off East Greenland is usually most extensive in April (Larsen, 1985) and the field operation was therefore scheduled for that month.
The last full summer of glacier-climate investigations at Qamanârssûp sermia, West Greenland
Authors: Braithwaite R.J
Published: June 2021

As part of the GGU programme of hydropower investigations in West Greenland, glaciological and climatological measurements were continued at Qamanarssiip serrnia in 1986. The station was first established in the late summer of 1979 so that records for seven complete summers 1980-1986 are now available. Brief reports on the work have been given by Olesen (1981), Olesen & Braithwaite (1982), Braithwaite (1983a, 1984, 1985a, 1986a). More detailed analyses and presentations of data are given in Braithwaite & Olesen (1982) and Braithwaite (1983b, 1985b). According to present plans, the Qamanarssup serrnia station will not be manned again for a full summer as it has been for the last seven years. However, a reduced programme of measurements will be continued in future years. A brief discussion of future plans is given at the end of this report.
Acritarchs from the Buen Formation (Lower Cambrian), North Greenland
Authors: Vidal G , Peel J.S
Published: June 2021

Siliciclastic sediments of the Buen Formation of North Greenland yield the earliest Cambrian fossils known from North Greenland, with the exception of cyanobacteria described from dolomites of the underlying Portfjeld Formation (see Peel, this report). The fauna is dominated by olenellid and nevadiid trilobites indicating an Early Cambrian age (Poulsen, 1974; Blaker, this report) but hyolithids, bradoriids, sponges and other fossils also occur. Bergstrom & Peel (this report) described trace fossils from the Buen Formation. Of particular interest is the recent discovery of lightly skeletised arthropods comprising an assemblage similar to that of the Middle Cambrian Burgess shale of Canada (Conway Morris et al., 1987).
Trace fossils from Silurian slope deposits, North Greenland
Authors: Pickerill R.K , Harland T.L
Published: June 2021

Nine ichnospecies are recorded from the lower part of the Wulff Land Formation (Early Wenlock) on the east side of the valley north of Apollo Sø in Wulff Land, western North Greenland. There, the formation consists of a siliciclastic slope sequence of dark grey mudstones interbedded with subordinate siltstones and sandstones. The trace fossils are: cf. Chondrites ichnosp., Gordia marina, Helminthopsis ichnosp., Megagrapton irregulare, Muensteria ichnosp., Neonereites multiserialis ichnosp. nov., Nereites jacksoni, Paleodictyon (Glenodictyon) imperfectum and Paleodictyon ichnosp. In addition to containing a new ichnospeciesy the assemblage documents only the second detailed account of trace fossils in Lower Palaeozoic slope sequences; most of the ichnospecies have not been recorded previously in such sequences.
Examples of bar accretion in fluvial sand, the Atane Formation, eastern Disko, West Greenland
Authors: Pedersen G.K , Jeppesen M.W
Published: June 2021

The aim of the present paper is to supply additional sedimentological observations and to add new details to the existing interpretation of the Atane Formation on eastern Disko. Examples of epsilon cross-bedding reflect formation of point bars and indicate intermittent development of sinuous channels in the coarse-grained braided river. Large tabularsets of planar cross-bedding are interpreted as transverse bars and the coalescerice of two such bars are discussed in detail. The field work was carried out during five days in July 1987 as part of a sedimentological research project supported by GGU and financed by SNF.
Reconnaissance investigations in the Skjoldungen region, South-East Greenland
Authors: Nielsen T.F.D , Escher J.C
Published: June 2021

From 1 July to 25 August 1987 a GGU expedition made reconnaissance investigations between 62°N and 64°20'N in South-East Greenland. The programme was a continuation of the investigations in the Ammassalikl Angmagssalik distriet in 1986 (Kalsbeek & Nielsen, 1987) and the completion of the fieldwork describing areas in East Greenland between 62°30'N and 65°45'N for the planned map sheet (no. 14) in the 1:500 000 geological map series. The Skjoldungen district was known mainly from previous boat-supported work in the coastal areas as described by Bridgwater & Gormsen, 1969; Andrews et al., 1971, 1973; Bridgwater et al., 1976; Escher & Nielsen, 1982, 1983; Nielsen & Escher 1985 and Escher et al., 1986.
Upper Palaeozoic bryozoans from the Wandel Sea Basin, North Greenland
Authors: Madsen L , Håkansson E
Published: June 2021

Bryozoans constitute a prolific but poorly known faunal element in most of the Upper Palaeozoic strata in North Greenland. Commonly bryozoans are the dominant fossil group, and occasionally their skeletons are rock-forming. Faunistic and taxonomic investigation has established the presence of at least 21 genera, representing all five Palaeozoic orders of Stenolaemata. However, estimates ofspecies diversity cannot be made until completion of a thorough re-evaluation of species concepts in all the groups present.
Non-toxic low-cost heavy liquid separation in the Geological Survey of Greenland
Authors: Schiøler P
Published: June 2021

Density separation of mineral and sediment grains into fractions using heavy liquids traditionally employs organic compounds such as bromoform (density 2.89) and tetrabromoethane (density 2.96) which are known to be toxic even at very low concentrations (Van Haaften, 1969) and possibly carcinogenic. In addition, the separated grains are washed with organic solvents such as acetone which may be highly inflammable, and are also a health risk. In recent years, a new water soluble compound, sodium polytungstate (SPT), 3Na2WO4.9WO3.H2O, has become available as a medium for heavy liquid separations, offering an alternative to the heavy organic liquids. Hs use has been discussed by several workers (e.g. Plewinsky & Kamp, 1984; Krukowski, 1988) in a variety of geological settings. The present note summarises experience in GGU's palaeontological laboratory gained from working with SPT for a full year as a replacement for tetrabromoethane and bromoform in the separation of phosphatic microfossils from samples principally of Lower - Middle Cambrian age. Apart from improving the work environment by replacing high health-risk chernicals with water soluble products without known detrimental effects, SPT has proved to be both an economical and potentially efficient alternative to the organic heavy liquids. SPT is patented, and only available from Sometu, Falkenried 4, D 1000 Berlin 33, Federal Republic of Germany.
Middle Proterozoic ultramafic lamprophyre dykes in the Archaean of the Atâ area, central West Greenland
Authors: Marker M , Knudsen C
Published: June 2021

During the mapping of gneisses and supracrustal rocks around Eqe in the eastern part of the Atâ area in 1988 a series of ultramafic dykes of lamprophyric affinity were discovered by the authors. The dykes are conspicuous in the field because of their lithology, with often high contents of carbonate, and the occurrence of brownish phlogopite phenocrysts. Their ductile type of deformation and aggressive aiteration of the wall-rock are distinctive. The purpose of this paper is to give a preliminary account of the mode of occurrence and lithology of the dykes based on the mapping results and a provisional inspection of a dozen thin sections. Their possibie age is discussed on the basis of their spatial relation to a large NNW-SSE trending dolerite dyke dated at 1645 ± 35 Ma by Kalsbeek & Taylor (1986).
Greenland ice-margin programme, a pilot study at Pâkitsoq, north-east of Jakobshavn, central West Greenland
Authors: Thomsen H.H , Olesen O.B , Braithwaite R.J , Weidick A
Published: June 2021

A glaciological field programme was carried out from 24 July to 21 August 1988 on the Greenland ice-sheet margin at Pakitsoq, north-east of Ilulissat/Jakobshavn, West Greenland. Glaciological investigations for planning hydropower at Pakitsoq have been made by GGU since 1982. The investigations include six years of mass-balance measurements, repeated photogrammetric and satellite mapping, ice-thickness mapping by radio-echo sounding, stable-isotope studies, hot-water-jet drillings and measurements of ice velocity and englacial temperatures (Thomsen, 1986, 1988; Thorning & Hansen, 1987; Olesen & Clausen, 1988). Simulations of runoff, glacier dynamics and glacier hydraulics are also carried out (Reeh, 1983; Thomsen et al., 1988). The aim of the 1988 field programme was to extend and confirm assumptions in the previous work.
Measurements of ice thickness on glaciers at Isortuarssûp tasia, southern West Greenland and Pâkitsoq, central West Greenland
Authors: Thorning L , Hansen E
Published: June 2021

Two separate geophysical projects were carried out in 1988 as part of glacier-hydrological investigations of the margin of the Inland Ice. We made a reconnaissance electromagnetic resonance survey over the ice margin adjacent to Sermilik and Isortuarssup tasia, south-east of Nuuk/Godthåb and measured ice thickness along some lines in the area of Qamanârssûp serrnia, Kangiata nunâta sermia and Kangaussarssup sermia a short distance to the north, as well as a few profiles over a local ice cap just east of Isortuarssup tasia. In the Pâkitsoq area, north east of Ilulissat/Jakobshavn, we finished the mono-pulse ice radar work started last year (Thorning & Hansen, 1988a).
Shelf sand banks and sand dune fields from the Volgian–Valanginian Raukelv Formation of Jameson Land, East Greenland
Authors: Surlyk F , Noe-Nygaard N
Published: June 2021

The aims of the present study were: to interpret precisely the depositional environment of the coarsegrained, cross-bedded sandstones of the Raukelv Formation (Lower Volgian - Valanginian) of Jameson Land; to explain the upwards transition over a few metres from the underlying deep-shelf mudstones and turbiditic sandstones ofthe Hareelv Formation; to make precise correlations and comparison with the Hartz Fjeld Formation of Milne Land to suggest an alternative to the fan delta interpretation of Sykes & Brand (1976) which was proved inadequate by Birkelund et al. (1984); and finally to place the Raukelv Formation better within the regional tectonic and provenance framework.
Facies mapping and reservoir evaluation of the Upper Permian Wegener Halvø Formation in Wegener Halvø, East Greenland
Authors: Stemmerik L , Scholle P.A , Thomas E , Amendolia M , Henk F.H , Uncini G
Published: June 2021

Field work was carried out from 17 July to 3 August by a joint group from ARCO, AGIP and GGU to evaluate the reservoir potential of the Upper Permian limestones in Wegener Halvø (fig. 1). The group was based south of Paradigmabjerg (fig. 1) and had a Bell 206 helicopter available tull-time during the entire period. Logistic support was provided by the ARCO base at Constable Pynt. The Upper Permian limestones in the Wegener Halvø area have been investigated previously by GGU (Stemmerik, 1979; Surlyk, 1983; Surlyk et al., 1984a,b, 1986a; Hurst et al., 1989). Diagenetic studies of the limestones (Scholle, 1986; Hurst et al., 1989) indicate that reservoir properties are expected mainly to occur in the bryozoan-cement mounds of the Wegener Halvø Formation. Accordingly, the 1988 programme concentrated on more detailed studies of these mounds and included a shallow drilling programme conducted by GGU (see Christiansen & Stemmerik, 1989).
Regional geological investigations and 1:500 000 mapping in North-East Greenland
Authors: Henriksen N
Published: June 2021

North-East Greenland is the last major area that remains to be geologicaIly mapped in the programme of regional mapping at a scale of 1:500000. In 1988 a three-year field mapping programme was initiated aimed at regional geological studies and geological mapping in the area between 75°N and 78°N. The southern third of this region (75°-76°N) is included on the map at a scale of 1:250000 by Koch & Haller (1971), and the n0rthern part forms part of a map at a scale of 1:1 000000 (Haller, 1983). However, the region as a whole has previously only been studied on a reconnaissance basis with limited ground control, and the published maps make extensive use of aerial photograph interpretation.
Programme of geochronology and isotope geochemistry in the Ammassalik region, South-East Greenland: outline and preliminary results
Authors: Kalsbeek F , Taylor P.N
Published: June 2021

Geological investigation of the Ammassalik region in the summer of 1986 included the collection of sample suites for isotopic dating. This report sets out the plans for future dating work, and presents some preliminary results on sample suites collected in 1986 and on earlier expeditions to the region. From the data now available it is clear that crustal evolution commenced during the Archaean and that further additions to the crust took place during early-to-mid-Proterozoic tectonothermal events. Some features of the geology of the Ammassalik region may be attributable to the collision of two Archaean continental blocks.
Supracrustal rocks in the Ammassalik region, South-East Greenland
Authors: Hall R.P , Chadwick B , Escher J.C , Vasudev V.N
Published: June 2021

Large belts of supracrustal rocks are abundant in the Ammassalik region of S.E. Greenland, and are referred to collectively as the Siportoq supracrustal association. They comprise overwhelmingly metasediments, mainly of quartz-rich or semipelitic composition, with variable proportions of quartz, kyanite, sillimanite, garnet and biotite. Graphitic schists are also common and marble horizons occur up to a kilometre thick. Garnet amphibolites are volumetrically minor, and ultramafic rocks are extremely rare. Lithological banding representing relict bedding and rare cross-bedding are locally well preserved. The compositions of the metasedimentary rocks suggest that their provenance was dominantly sialic and the great thickness of semi-pelitic rocks suggests that additions of immature minerals kept pace with gentle subsidence of a basin or shelf environment. The thick marble horizons indicate periods of relative stability. Unlike the surrounding quartzo-feldspathic gneisses in the north of the area, the supracrustal rocks do not appear to have undergone granulite facies metamorphism.
Precise age for the Ammassalik Intrusive Complex
Authors: Hansen B.T , Kalsbeek F
Published: June 2021

An age of IR86 ± 2 Ma has been obtained on zircons from a diorite sample of the Ammassalik lntrusive Complex.
Discovery of sapphirine in East Greenland
Authors: Brooks C.K
Published: June 2021

An occurrence of sapphirine is described from the Kronprins Frederik Bjerge (about 67°N) in East Greenland. It occurs in an assemblage with phlogopite, spinel and orthopyroxene in a thin band in quartzo-feldspathic gneisses of granulite facies but may well be much more widespread in the area.
Current activities in the field of hydrocarbon geology
Authors: Stemmerik L , Pulvertaft T.C.R , Larsen H.C
Published: June 2021

GGU has two principal functions in the field of hydrocarbon geology: (1) to identify and investigate sedimentary basins with hydrocarbon potential, in order to obtain information that can attract and guide industry in its choice of target areas for exploration, and (2) on the basis of the insight gained from (1), to advise the Mineral Resources Administration for Greenland in technical matters concerning the administration of licences and concessions.
Disko Bugt Project, central West Greenland
Authors: Kalsbeek F
Published: June 2021

One of GGU’s major field activities in 1989 took place in July and August in the north-eastern part of the Disko Bugt region, mainly north of Illulissat (Jakobshavn) (fig. 1). This was the second year of the ‘Disko Bugt Project’, planned for 1988–1991, with one summer's break in 1990. The project spreads over various activities and over two very different geological provinces: the Archacan-Proterozoic basement east and north-east of Disko Bugt and in the eastern part of Nugssuaq, and the Cretaceous-Tertiary basin in the west, on Disko and the western part of Nugssuaq. The main aim of the project is to provide a background for the evaluation of the economic potential of the region mineral resources in the Precambrian basement, and the hydrocarbon potential of the basin.
A gold mine in East Greenland?
Authors: Nielsen T.F.D
Published: June 2021

The search for gold in Greenland has hitherto been concentrated in geological terrains such as Precambrian volcanics that elsewhere on earth are traditionally regarded as gold-bearing. However, as it happens, the first exploitation of gold in Greenland could well be from a truly new type of gold mineralisation.
Investigating Greenland's glaciers
Authors: Weidick A
Published: June 2021

Investigations of Greenland's glaciers undertaken by GGU are primarily related to the exploitation of meltwater from the Inland lce and local glaciers in western Greenland, i.e. they are essentially related to glacier hydrology (Olesen & Braithwaite, 1989). The studies are therefore based on mass balance data combined with investigations of superglacial melt/refreezing and the determination of the internal mode of drainage. Related to this work is the documentation of short-term glacier changes at specific localities identified as being of special interest for hydropower from the point of view of glacier hazards, i.e. for example damage caused by tapping of ice dammed lakes or change of proglacial draining caused by change in the glacier's thickness and extent. Similar documentation of long-term glacier fluctuations provides a background for control and modelling of past glacier fluctuations. The procedures have a direct bearing on the calculation of scenarios for future events related to the individual localities or, in a regional sense, to the impact of changes in Greenland glaciers on global sea level (the 'greenhouse effect’).
The Devonian basin project, North-East Greenland – a summary
Authors: Larsen P.-H , Olsen H
Published: June 2021

As part of the general studies of Phanerozoic basin development and onshore hydocarbon potential in East Greenland undertaken by tile Geological Survey of Greenland (GGU) in the years 1986–1990, integrated structural and sedimentological studies of the Devonian basin in North-East Greenland (Fig. 1) were carried out in order to gain an understanding of the early basin formation folIowing the Caledonian orogen (Marcussen et al., 1987, 1988; Larsen et al., 1989). The immediate relevance of the Devonian basin studies lies in the necessity of having first-hand knowledge of the structural style and sedimentary history of the exposed part of the basin, in the deeper seismic image and early history of the Jameson Land basin farther to the south are to be understood (H. C. Larsen et al., 1989).
Project SYD VEST SEIS - 3285 km of multichannel seismic data acquired on the southern West Greenland shelf
Authors: Chalmers J.A , Dahl-Jensen T
Published: June 2021

During the three years since 1988, there has been renewed activity within the Geological Survey of Greenland (GGU) to reassess the geology and petroleum prospectivity of the southern West Greenland offshore area (Chalmers, 1989; Chalmers, 1990; Chalmers & Pulvertaft, in press; Ottesen, 1991). Pulvertaft (1991) gives a summary of the present state of the re-evaluation. This work has shown that the geology of the northern Labrador Sea and offshore southern West Greenland is poorly understood. A number of questions about the area's petroleum prospectivity remain unanswered despite re-interpretation and in some cases reprocessing of the existing seismic data. These problems derive from limitations in both the quality and extent of the existing seismic coverage.
The Black Angel lead-zinc mine 1973–90
Authors: Thomassen B
Published: June 2021

On 25th July 1990 the last ore was processed in the ore dressing plant at Mårmorilik thereby terminating seventeen years exploitation of the Black Angel (Sorte Engel) lead-zinc deposit (Fig. 1). During that period some 1.4 million tons zinc, 0.4 million tons lead and 250 tons silver have been extracted from the deposit which originally comprised 13.6 million tons ore grading 12.3% Zn, 4.0% Pb, 29 ppm Ag and 13.7% Fe (Table 1). The mining operations ceased because the extractable ore reserves were exhausted.
Registration of kimberlites and other potentially diamond-bearing rocks in Greenland
Authors: Larsen L.M
Published: June 2021

Kimberlites are potentially diamondiferous rocks. They have been found at a number of localities in Greenland (Fig. 1), notably in the Holsteinsborg-Sarfartoq region and south of Frederikshåb (Andrews & Emeleus, 1971, 1975, 1976; Larsen, 1980; Scott, 1977, 1979, 1981; Thy et al., 1987). Prospecting for diamonds and kimberlites was carried out by several mining companies in West Greenland in the years 1970-1988.
Publications of the Geological Survey of Greenland 1990
Authors: Editorial Team
Published: June 2021

No abstract available.
Present-day expansion of the southern part of the Inland Ice
Authors: Weidick A
Published: June 2021

In connection with the work on a West Greenland glacier atlas and glacier inventory the activity of a c. 1200 km long segment of the Inland lce was investigated for the years 1950 and 1985. Around 1950 major parts of the ice margin were in a state of thinning and recession and exceptions were mainly confined to restricted highland areas where evidence of advance could be located. Updating of the conditions to 1985 reveals that marginal advances have now spread to parts of the adjoining lowland areas indicating a 'turn of the tide' where the general period of recession since last century to around 1950 is now substituted by a major tendency for advance.
A lamproite stock with ellipsoidal phlogopite nodules at Oqaitsúnguit, Disko Bugt, central West Greenland
Authors: Skjernaa L
Published: June 2021

A small stock containing a medium- to coarse-grained phlogopite-rich lamproite occurs in the Archaean Ata granitoid in West Greenland. It was emplaced by a combination of forceful intrusion and assimilation. Metasomatic alteration has taken place in the country rock near the stock and in xenoliths. Although there are similarities with other lamproites, the Oqaitsunguit lamproite differs with respect to (1) mineralogy. The main mineral phases are phlogopite, microcline, K-richterite, K-Mg-arfvedsonite, aegirine-augite and diopside; (2) coarse grain size; (3) low whole-rock TiO2, FeO and SiO2 contents; (4) low TiO2 in phlogopites and amphiboles; (5) the presence of 0.5–6 cm long ellipsoidal phlogopite nodules, which occur scattered throughout the rock. Each phlogopite nodule is composed of a central phlogopite grain, which is enveloped by a mantle or shell of another phlogopite grain.
GGU's aktiviteter i 1991
Authors: Ghisler M
Published: June 2021

GGU's arbejde har i 1991 været præget af en opfølgning af de politiske bestræbelser på at opnå øget aktivitet på råstofområdet. Al geologisk information om Grønland registreres i GGU og søges præsenteret i en let tilgængelig form for olie- og mineselskaber.
Greenland glaciers and the 'greenhouse effect', status 1991
Authors: Braithwaite R.J , Reeh N , Weidick A
Published: June 2021

Possible global climate change caused by increased 'greenhouse effect' continues to be a matter of international public concern. In particular, a warmer climate is expected to cause increased melting of the Greenland ice sheet, and a rise in world sea level. The Greenland ice sheet is therefore a potential hazard for low-Iying countries. Climate warming may be apparent first, and with greatest magnitude, at high latitudes so that increased melting of the Greenland ice sheet could give early warning of global climate change. For these reasons, GGU and foreign organisations are studying Greenland glaciers in connection with the 'greenhouse effect' (Fig. 1). The present review updates the note by Braithwaite (1990).
Bjørnesund Project, West Greenland
Authors: Appel P.W.U
Published: June 2021

The Bjørnesund Project is aimed at an evaluation of the mineral potential of the southernmost part of the municipality of Nuuk, between Bjørnesund and the large glacier Frederikshåb Isblink. One of the reasons that economic mineral deposits were expected to occur in the Bjørnesund area, was the presence of gold anomalies in heavy mineral concentrates from stream sediments (Appel, 1989). Another reason was the presence of anthophyllite-rich zones, presumed to have formed by hydrothermal alteration. At a fairly late stage in the planning of the field programme, the project was enlarged to include a regional geochemical stream sediment sampling programme in the area between 64°N and Bjørnesund. This latter part of the project was financed by a separate contribution from the Mineral Resources Administration, Ministry of Energy.
Renewed petroleum geological studies onshore West Greenland
Authors: Christiansen F.G , Dam G , McIntyre D.J , Nøhr-Hansen H , Pedersen G.L , Sønderholm M
Published: June 2021

As a consequence of renewed interest in petroleum exploration in West Greenland (e.g. Pulvertaft, 1991: Christiansen & Pulvertaft 1992; Gil & Gas Journal, 1991; Chalmers & Pulvertaft, in press) the Geological Survey of Greenland (GGU) has begun a new series of petroleum geological investigations of the Upper Cretaceous – Lower Tertiary sediments exposed on Disko. Nugssuoq and Svartenhuk Halvø (69°–72°N) (Fig. 1). These sediments include the only marine sediments of this age exposed in the entire Labrador Sea–Baffin Bay region. and studies of these are essential for a detailed interpretation of the offshore geology (Chalmers, 1990, 1991; Ottesen, 1991a, b). Field work on the marine succession has been concentrated on three main tasks: detailed sedimentological studies; sampling for palynological and organic geochemical studies; and mapping and structural analysis, in order to gain a detailed knowledge of both early basin development in West Greenland the three-dimensional architecture of deltas and submarine fans. The petroleum geological studies are being coordinated with ongoing studies of age-equivalent non-marine strata being carried out by the University of Copenhagen, and with several other externally finance projects.
New geological map of the Thule region, North-West Greenland
Authors: Dawes P.R
Published: June 2021

Map sheet no. 5 (Thule), part of the 14-map geological map series at 1:500 000 covering the onshore geology of Greenland, was published in 1991 (Dawes 1991; Fig. 1). The Thule map covers the northern part of the west coast of Greenland between latitudes 75° 15' and 78°N, including the region traditionally known as the Thule or Kap York district (Figs 1 & 2). The southern part of the map covers the relatively inaccessible coast of Melville Bugt, known as the Lauge Koch Kyst. Here the Inland Ice reaches the sea along a broad front leaving land exposed only as nunataks, semi-nunataks, ice-rooted peninsulas and islands.