bluuebunny/crossref_metadata_2025 huggingface dataset:
Quaternary, pre-Holocene, marine events of western Greenland
Authors: Kelly M
Published: June 2021

Lithological, faunal, radiocarbon and amino acid data are presented for ten new occurrences of in situ or redeposited pre-Holocene marine material in western Greenland, and further data on four previously described ones, bringing the total known occurrences to 22-23. The new and older data suggest that this material dates from a number of periods of marine inundation from the Early to Late Quaternary, the exact number being uncertain. A succession of marine events are designated for two regions of western Greenland. From the occurrence of the Chiamys islandica - Mytilus edulis faunal assemblage the subarctic West Greenland Current is considered to have existed during several of these marine events of different age.
The Ordovician trilobite Pseudogygites from Greenland
Authors: Lane P.D
Published: June 2021

A single pygidium from GGU sample 316082 here referred to Pseudogygites Kobayashi, 1934 represents the first record of this genus from Greenland (fig. 1). It was collected from the Aleqatsiaq Fjord Formation at the type scction in Washington Land, western North Greenland from the dark shale noted by Hurst (1980, p. 17, fig. 7).
Cambrian platform - outer shelf relationships in the Nordenskiöld Fjord region, central North Greenland
Authors: Ineson J.R , Peel J.S
Published: June 2021

Cambrian sequences around the head of Nordenskiöld Fjord, central North Greenland, preserve the transition from platform interior carbonates of the Ryder Gletscher Group (redefined) to outer shelf-slope and platform margin sequences assigned to the Brønlund Fjord and Tavsens Iskappe Groups. Study of this transition has allowed redefinition and integration of these two stratigraphic schemes. Shallow subtidal to intertidal, well-bedded carbonates of the platform interior grade north-eastwards into high-energy grainstones and algal boundstones of the platform margin complex. Platform foreslope facies show well-developed clinoform bedding and wedge out into dark carbonates and clastics of the outer shelf sequence.
U-Pb and Rb-Sr age determinations on Caledonian plutonic rocks in the central part of the Scoresby Sund region, East Greenland
Authors: Hansen B.T , Steiger R.H , Henriksen N , Borchardt B
Published: June 2021

Five new U-Pb age determinations on zireons and three new or reanalysed Rb-Sr age determinations of some of the late orogenie plutonic bodies from the Gåseland - Stauning Alper migmatite and granite zone in the Scoresby Sund region, give Caledonian ages between 428 Ma and 352 Ma. Together with previously published age determinations they suggest a main intrusive epoeh around 420 Ma with the last intrusive events as late as 390 - 350 Ma. In addition analytical data for six previously published Rb-Sr ages from the region are reassessed and presented in full.
Isotopic age dating in Liverpool Land, East Greenland
Authors: Hansen B.T , Friderichsen J.D
Published: June 2021

In Liverpool Land in the eastern part of the Scoresby Sund region gneisses and migmatites were intruded by a number of intermediate plutonites and by younger granites. A number of K-Ar, Rb-Sr and U-Pb isotope age determinations indicate that: 1) the gneisses have a pre-CaIedonian as well as a CaIedonian history, 2) the migmatites were thoroughly reworked during the late part of the Caledonian orogeny, while 3) the plutonic rocks all seem to have been intruded during the Caledonian orogeny.
Rb-Sr and K-Ar Caledonian ages from the Upper Eleonore Bay Group and Cambrian metasediments of the East Greenland Caledonian fold belt
Authors: Bonhomme M.G , Caby R
Published: June 2021

Fine sediment fractions < 2 u extracted from various formations of Upper Proterozoic and Cambrian age in Canning Land and Segelsällskapet Fjord in East Greenland are anchimetamorphic to strongly diagenetic. Rb-Sr and K-Ar isotopic analyses indicate that the metamorphic and diagenetic changes correspond to the main Caledonian event at c. 450 Ma while some of the data are consistent with ayounger event at nearly 400 Ma, possibly connected to late Caledonian tectonics. The study also shows the peculiar features of the isotopic diagrams often observed in such conditions: parallel isotopic lines, discordant behaviour of the Rb-Sr and K-Ar chronometers, and the necessity of collecting sets of samples from small homogeneous areas.
Radiocarbon dating of samples collected during the 1984 expedition to North Greenland
Authors: Bennike O , Kelly M
Published: June 2021

The results of 18 radiocarbon age determinations on shelIs (14), plant material (2) and bone (2) are summarised here. The samples were collected during the GGU expedition to central and western North Greenland in 1984 (Henriksen, 1985). This list adds to the list published by Kelly & Bennike (1985). In addition, a series of dates from Hall Land and Nyeboe Land has recently been published by England (1985).
New sedimentological data on Tertiary shales from Disko and Nûgssuaq, West Greenland
Authors: Pedersen G.K
Published: June 2021

The sedimentological data described and discussed below were collected during a period of 47 days in the summer of 1986. The fjeld work was carried out over 23 days from four camps: Tartunaq, Akuneq, Skansen and Tuapait (fig. 1). The main objective was investigation of the Naujat Member, through which a number ofsections were measured, but in addition the under- and overlying, predominantly sandy facies associations were also studied.
Reconnaissance for economic minerals in the Kangerdlugssuaq area, East Greenland
Authors: Brooks C.K , Schønwandt H.K , Stenstrop G
Published: June 2021

As an intergral part of GGU's work in East Greenland in 1986 (Kalsbeek & Nielsen, this report) a party visited the Kangerdlugssuaq area with a view to assessing its economie potential. Logistic support was shared with the Geodetic Institute. During most of the period spent in the field area (27 July to 12 August) Stenstrop, assisted by Henrik Krarup (a student assistant), worked on Flammefjeld, a porphyry molybdenum prospeet earlier investigated by the Northern Mining Company of Copenhagen (Geyti & Thomassen, 1984), while Brooks and Sehønwandt investigated other targets and eo-operated closely with Platinova Resources Ltd of Toronto who have a eoneession in the area. Kangerdlugssuaq is an area of Arehaean gneisses whieh was subject to intense magmatie activity in the early Tertiary when the present continental margin was loeated over the hot spot whieh now lies under Iceland. The geology has reeently been reviewed by Brooks & Nielsen (1982), where loealities mentioned here ean be identified.
Electromagnetic reflection survey 1986 at the Inland Ice margin of the Pâkitsoq basin, central West Greenland
Authors: Thorning L , Hansen E
Published: June 2021

The first successful application of electromagnetic ref1ection (EMR) techniques for determination of ice thickness in the outermost margin of the Inland Ice adjacent to the Pâkitsoq basin took place in luly 1985 (Thorning et al., 1986). Although the survey was planned as a series of experiments to examine why previous attempts had not worked, the EMR data acquired were of very good quality and could be compiled into a preliminary map of ice thickness and a map of the subglacial topography over part of the region. Thus, by early 1986 it Rapp. Grønlands geol. Unders. 135, 87-95 (1987) was known that the method worked and could be compiled through to the final product. With the increasing interest in this region, which is the planned location of the first hydroelectric power plant in Greenland, it was necessary to return in 1986 to survey the area in greater detail and to extend the coverage to the east. This note describes the field work carried out in April 1986 and the subsequent compilation and analysis of the combined EMR data sets from 1985 and 1986.
Early Tertiary, low-potassium tholeiites from exploration wells on the West Greenland shelf
Authors: Hald N , Larsen J.G
Published: June 2021

Data on the Tertiary basalts in the Davis Strait region are reported from two exploration wells drilled by Arco and Mobil on the West Greenland shelf. Hellefisk 1 (67°53 'N, 56°44'W), situated only 60 km east of the mid-line in Davis Strait, penetrated the upper 690 m of a subaeriallava sequence continuous with the onshore volcanics of Disko and situated beneath 2.3 km of Paleocene to Quaternary sediments. The lavas are feldspar microporphyritic tholeiites and mostly unmetamorphosed despite the presence of laumontite and prehnite in the vesicular top zones. Nukik 2 (65°38'N, 54°46'W) penetrated 150 m of hyaloclastites and tholeiitic olivine dolerite sheets, presumably sills, some 200 km further to the south. These vo1canics are also deeply buried and are of unknown extension. The drilled rocks, except for the much altered hyaloclastites in the Nukik 2 well, have low contents of Ti02 (0.99-2.03%), K2O (0.09-0.18%) and P2O5 (0.08-0.21%), La/Sm ratios less than one and 87Sr/86Sr ratios of 0.7032 to 0.7044. Chemically they are related to the MORB-like picrites of Baffin Island rather than the less depleted tholeiites of West Greenland. In both areas the MORB affinity may be related to eruptions through a strongly attenuated lithosphere associated with the opening of Baffin Bay and Davis Strait.
Spirellus and related helically coiled microfossils (cyanobacteria) from the Lower Cambrian of North Greenland
Authors: Peel J.S
Published: June 2021

Phosphatised helically coiled microfossils are described from the Portfjeld Formation of Early Cambrian age in southem Peary Land, central North Greenland. SpirelIus Jiang in Luo et al., 1982, originally described from the Meishucunian Stage of China, is recorded from Greenland and interpreted as a filamentous cyanobacterium showing variable degrees of mineralisation of the sheath. Jiangispirellus groenlandicus gen. et sp. nov. is described, based on helically coiled naked trichomes with preserved cell structure. Both genera are compared to Obruchevella Reitlinger, 1948 which is also reported from Greenland for the first time.
Acritarchs from the Kap Holbæk Formation, North Greenland
Authors: Peel J.S , Vidal G
Published: June 2021

In two recent general summaries of the geology of northern Greenland (Peel, 1986; Higgins et al., in press) brief reference was made to acritarchs from the Kap Holbæk Formation of eastern North Greenland indicative of a Proterozoic age. The age determination is of particular interest since the formation has been interpreted widely as of Cambrian age. This short note more fully documents the evidence for this revised age determination.
Lower Cambrian trace fossils from northern Greenland
Authors: Bergström J , Peel J.S
Published: June 2021

Rusophyciform and cruzianaeform trace fossils are described from Lower Cambrian siliciciastic shelf deposits in North-West and North Greenland. Cruziana cf. C. dispar Linnarsson, 1869 is reported from the Dallas Bugt Formation of Inglefield Land while a new ichnospecies, Rusophycus marginatus, occurs in the Buen Formation of Peary Land and in the equivalent Humboldt Formation of Daugaard-Jensen Land. These species show no similarity to the Cruziana sp. previously described from East Greenland. The occurrence of C. cf. C. dispar could indicate some similarity in Cambrian trace fossil 'ichnofaunas' between Greenland and Europe but available material is insufficient to ciarify this relationship.
The small shelly fossil Mongolitubulus from the Lower Cambrian of central North Greenland
Authors: Peel J.S , Blaker M.R
Published: June 2021

The problematic small shelly fossil Mongolitubulus Missarzhevsky, 1977 is reported from the Henson Gletscher Formation of late Early Cambrian age (Bonnia-Olenellus Zone) in southem Freuchen Land, central North Greenland. Mongolitubulus is described from strata of similar Early Cambrian age (Botomian) in Mongolia and Kazakhstan, and is also reported from Antarctica. The Greenland Mongolitubulus is the first record of the genus from the North American continent.
The Wandel Valley Formation (Early - Middle Ordovician) of North Greenland and its correlatives
Authors: Peel J.S , Smith M.P
Published: June 2021

Members are formally described within the Wandel Valley Formation (Early - Middle Ordovician) of the Ryder Gletscher Group in central and eastem North Greenland. In Peary Land the names Pyramideplateau Member (the combined lower and middle informal members of previous usage) and Vestervig Elv Member (the upper member) are proposed. In Kronprins Christian Land, the Alexandrine Bjerge Member (new) overlies the previously named Danmarks Fjord and Amdrup Members. Conodont studies, supported by the macrofauna, indicate that the Pyramideplateau, Danmarks Fjord and Amdrup Members are of late Canadian (Early Ordovician) age. The Canadian-Whiterockian boundary lies within the lowermost part of the Vestervig Elv and Alexandrine Bjerge Members. The top of the former is of earliest Late Whiterockian age while the Alexandrine Bjerge Member only extends into the late Middle Whiterockian. The members of the Wandel Valley Formation are correlated with coeval successions in western North Greenland, East Greenland, the Canadian Arctic Islands and Svalbard.
Electromagnetic reflection survey 1987 in key areas of the Pâkitsoq basin at the margin of the Inland Ice, central West Greenland
Authors: Thorning L , Hansen E
Published: June 2021

The EMR surveys of previous years (Thorning et al., 1986; Thorning & Hansen, 1987) provided the ice-thickness data necessary for a detailed evaluation of the glaciological-hydrological conditions of the Inland Ice required for planning a hydropower plant at Pâkitsoq (Thomsen et al., 1986). This evaluation also identified some locations where ambiguity in the hydrological interpretation resulted in uncertainties in the estimate of water supply to the Pâkitsoq basin, because the data available did not allow the model to predict the direction of drainage of meltwater. Therefore, further geophysical work was undertaken to provide more detailed information on the subglacial relief of these localities on the ice.
Gravity and magnetic susceptibility survey over the northern part of the supracrustal rocks in the Disko Bugt area, central West Greenland
Authors: Thorning L
Published: June 2021

As part of the Disko Bugt project (Kalsbeek, 1989) a survey of gravity and magnetic susceptibility was carried out over parts of the supracrustal rocks and the Atå granite/tonalite (fig. 1). The objective of the survey was to acquire new geophysical data that, together with the existing regional aeromagnetic survey in the area (Thorning, 1988), can be used to study the deeper structures related to the granite and the supracrustal belts in the area.
Continued stable isotope studies on the Greenland ice-sheet margin at Pâkitsoq, north-east of Jakobshavn, central West Greenland
Authors: Reeh N , Letréguilly A , Oerter H
Published: June 2021

In close cooperation with the GGU glacier-hydrologicaI field team a small group from the Alfred Wegener Institute for Polar and Marine Research (AWI), Bremerhaven, West Germany, worked for four weeks in July-August 1988 on the West Greenland ice-sheet margin at Paakitsup Akuliarusersua, about 40 km northeast of Ilulissat/Jakobshavn. Previous stable isotope studies in the area by GGU (Reeh & Thomsen, 1986) have documented that ice deposited in the inland regions of the ice sheet during the last ice age is now exposed as a roughly 600 m wide band at the surfaee of the ice sheet near the ice edge (Reeh et al., 1987a). The main purpose of the AWI expedition was to perform detailed (continuous) surfaee sampling for stable isotope analysis (bIBO) through the transition from the last glacial period (Wisconsinan) to the present post-glacial period (Holocene). A comparison of such a detailed isotopic record from the surface of the ice margin with similar records from deep Greenland ice cores should tell how well the continuity of the layer sequence is preserved in the ice-margin record. This question is of crucial importance for evaluating the potential yield of the ice margin as a source of easily accessibie old ice.
Glacier-climate studies 1987-1988 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 made at the Qamanarssup sermia field station for the seven summers 1980- 1986. However, the station was deactivated at the end of the 1986 field season (Braithwaite, 1987) and only a reduced measurement programme was carried out in 1987-1988.
Sedimentological studies of the Upper Triassic to Lower Jurassic succession in the Jameson Land Basin, central East Greenland
Authors: Dam G
Published: June 2021

Sedimentological studies of the Upper Triassic to Lower Jurassic succession in central East Greenland were initiated in 1987 as a three-year research fellowship programme supported by British Petroleum Development, London (Dam, 1988). The study is primarilya lithofacies analysis, but ichnology, palynology sourcerock analysis, porosity/permeability analysis and diagenetic studies are also included in the programme. The stratigraphic interval includes the Kap Stewart and Neill Klinter Formations which have many features in common with stratigraphically equivalent formations in offshore mid- and northem Norway that form some of the most important potential petroleum reservoirs in these areas.
Upper Proterozoic and Lower Palaeozoic strata in northern East Greenland
Authors: Hambrey M.J , Peel J.S , Smith M.P
Published: June 2021

The Caledonides of East Greenland contain the best exposures of Upper Riphean to Ordovician sediments in the Arctic - North Atlantic region. At its thickest the sequence contains 13 km of Eleonore Bay Group clastic sediments and carbonates, the 0.8 km thick Tillite Group and 3 km of Cambro-Ordovician strata (Henriksen & Higgins, 1976; Henriksen, 1985). These sediments crop out in a belt stretching for nearly 300 km through the fjord region, between 71° 38' and 74° 25'N. Those in the northern part of the region, between Brogetdal in Strindberg Land and southern Payer Land, and especiaIly Albert Heim Bjerge and C. H. Ostenfeld Nunatak, were the subject of investigation during 1988 (figs 1, 2).
The geology and structural setting of the Proterozoic Ammassalik Intrusive Complex, East Greenland
Authors: Friend C.R.L , Nutman A.P
Published: June 2021

The rocks of the Ammassalik area comprise reworked Archaean gneisses and a variety of mainly pelitic to psammitic Proterozoic metasediments. Proterozoic deformation caused thrust intercalation of the rocks and folded them into overturned, southerly directed nappes. Three dioritic centres, collectively named the 'Ammassalik Intrusive Complex' in this paper, were emplaced into a tract occupied by metasediments, causing extensive anatexis. The granitic liquids produced from this resulted in magma mixing with the still liquid diorite; they also formed discrete sheets of augen granite intruding the country rocks. The diorite centres were emplaced as relatively dry bodies, and together with anatexis, they caused the formation of granulite facies assemblages by dehydration reactions in the country rocks. Further away from the contact zone garnet appeared in the surrounding grey gneisses.
The Blokken gneisses: a re-appraisal
Authors: Dawes P.R , Friend C.R.L , Nutman A.P , Soper N.J
Published: June 2021

A group of quartzo-feldspathic gneisses – the Blokken gneisses – is described in the literature as a syn-tectonic igneous suite intruded into the central part of the Nagssugtoqidian mobile belt of South-East Greenland in early Proterozoic time. The gneisses are reported to be transgressive to early structures (Nag. 1) and to show only later (Nag. 2) tectonic fabrics. Field data are at variance with this interpretation. No grounds exist for maintaining the gneisses in question as a distinct unit separable from the regional Archaean gneisses. Consequently the term should be abandoned.
Geological mapping of Greenland
Authors: Dawes P.R
Published: June 2021

Geological maps provide an important means of documenting and advancing geological knowledge. As well as presenting detailed information in a practical way, geological maps are essential in assessing a region’s geological history; they are prerequisite for meaningful evaluation of mineral resources.
The Archaean Skjoldungen alkaline province, South-East Greenland
Authors: Nielsen T.F.D , Rosing M.T
Published: June 2021

An alkaline province has been found to constitute a significant part of the Archaean terraines in the Skjoldungen area, 63°N in South-East Greenland. A total of twenty-four alkaline complexes and syenite gneiss areas has been identified. The alkaline magmatism is regarded as syn- to post-tectonic to judge from the wide variation in the degree of deformation. A large number of intrusions are virtually undeformed. Petrographically the province encompasses slightly SiO2-undersaturated mafic to SiO2-saturated syenitic rocks and a carbonatite-bearing nephelinitic complex. Neodymium-samarium model ages and a zircon age show the alkaline rocks to be c. 2800 Ma old and the province thus constitutes the largest group of Archaean alkaline rocks yet found on Earth. The chemical characteristics, including very low concentrations of most trace elements except Ba and Sr, recall those of the younger alkaline Seiland province in Norway and the Haliburton-Bancroft province in Canada.
Sedimentological investigations of the Multicoloured 'series' (Eleonore Bay Group, Late Precambrian) in the Scoresby Land – Andrée Land region, North-East Greenland
Authors: Sønderholm M , Tirsgaard H
Published: June 2021

The approximately 1200 m thick Multicoloured 'series' (bed-groups 7–13) and adjacent units of the upper Eleonore Bay Group have been the subject of detailed sedimentological investigation during 1989 in the area between northern Scoresby Land and Andree Land in North-East Greenland. The Multicoloured 'series' consists of alternating units, 100–300 m thick, of carbonate and siliciclastic deposits which are uniformly developed throughout the central fjord zone. It represents the transitional stage from a pure siliciclastic shelf environment to a carbonate platform environment. During its development initial carbonate sedimentation was repeatedly terminated by drowning and siliciclastic deposition, until a large carbonate platform represented by the overlying Limestone-Dolomite 'series' was firmly established.
GGU's photogeological laboratory: aerial photogrammetry – a valuable geological mapping tool in Greenland
Authors: Hougaard G , Jepsen H.F , Neve J.K
Published: June 2021

Geological mapping in Greenland is generally greatly helped by the use of vertical aerial photographs. Bedrock surfaces are normally well exposed, vegetation is sparse in most parts of the country and glacial deposits can be scattered or completely washed away. Consequently, geological features such as bedding, stratigraphical boundaries and large-scale structures are commonly visible on aerial photographs. Since its establishment in 1946 as an independent institution, the Geological Survey of Greenland (GGU) has made extensive use of aerial photographs during mapping campaigns, and photogeological interpretation has played an important role in Copenhagen during map compilation.
Meltwater refreezing in the accumulation area of the Greenland ice sheet: Pâkitsoq, summer 1991
Authors: Braithwaite R.J , Pfeffer W.T , Blatter H , Humphrey N.F
Published: June 2021

There is public concern that warmer climate in the future may cause extra melting of glaciers, including the Greenland ice sheet, with a resulting rise in World sea level (Warrick & Oerlemans, 1990). Recent estimates of sea level rise from Greenland include 0.36–0.48 mm/year per °C temperature rise (Braithwaite & Olesen, 1990) but much work is still needed to make reliable forecasts.
Geological setting of Precambrian supracrustal belts: a fundamental part of mineral resource evaluation in Greenland
Authors: Dawes P.R , Schønwandt H.K
Published: June 2021

In Precambrian shield areas the economic potential of supracrustal rocks is well documented, and some of the world's largest metal deposits are found within these sequences. The Black Angel lead-zinc stratabound mineralisation at Mårmorilik in central West Greenland (71° 10'N, Fig. 1), hosted in the Proterozoic Karrat Group, is one commercial enterprise that confirms that this potential can be realised in Greenland. In last year's volume of Report of Activities, Thomassen (1991a) gave a history of the geology and mineral exploration of the Black Angel deposit.
Geomorphological applications of multi-model photogrammetry
Authors: Humlum O
Published: June 2021

The application of multi-model photogrammetry to steep cliff faces is described and examples given of the manipulation of the digitised data to produce three-dimensional terrain models, and by using other software models to estimate surface radiation balance.
Lithostratigraphy and geological setting of Upper Proterozoic shoreline-shelf deposits, Hagen Fjord Group, eastern North Greenland
Authors: Clemmensen L.B , Jepsen H.F
Published: June 2021

During the Late Proterozoic a more than 1000 m thick succession of sediments was deposited on the shelf fringing the north-eastern corner of the Greenland craton. These sediments were classified together with an underlying turbidite sequence in the Hagen Fjord Group (Haller, 1961), which is here redefined to contain only Upper Proterozoic, mainly shallow marine shelf deposits outcropping between Independence Fjord and Kronprins Christian Land in eastern North Greenland. Both siliciclastic and carbonate sedimentation occurred during the Late Proterozoic, and the changing tectonic environment along the northern and eastern shelf-margin of Greenland at that time is well recorded within the sediment sequence. Correlation of the Hagen Fjord Group with similar shelf deposits elsewhere along the eastern and northern margin of the Canadian-Greenlandian Shield is discussed.
Greenland MINEX News: a new service for the mining industry
Authors: Dawes P.R , Thomsen H.H
Published: June 2021

In the last few years there has been increased political awareness of the urgency to ensure the continuing and long-term involvement of the mining industry in Greenland's economy. Formalisation of this came in 1990 when an ad hoc working group was convened by the Danish Ministry of Energy and the Chairman of the Greenland Home Rule Authority with the purpose of working out a draft for a new strategy for exploration and utilisation of mineral resources in Greenland. The report containing specific recommendations was released the same year, the text being made available in Danish, English and Greenlandic (MRA, 1990).
Project SUPRASYD 1992: opening season in the Ketilidian of South Greenland
Authors: Nielsen T.F.D , Chadwick B , Dawes P.R , Frith R.A , Schønwandt H.K
Published: June 2021

Project SUPRASYD was initiated in summer 1992 with a helicopter-supported field programme carried out between the end of June and mid-August. As outlined in last year's Report of Activities (Dawes & Schønwandt, 1992) the major aim of SUPRASYD is to provide an economic assessment of the Proterozoic Ketilidian mobile belt that forms the southern tip of Greenland (Fig. 1). In particular focus are supracrustal rocks and later intrusions.
Neoglacial change of ice cover and the related response of the Earth's crust in West Greenland
Authors: Weidick A
Published: June 2021

The cooling trends of Neoglacial time caused re-formation of minor local glaciers and expansion of the Inland Ice margin. A consequence of this glacial reactivation in West Greenland was the conversion of an early Holocene glacio-isostatic emergence to Neoglacial submergence. Although the major trends of fluctuations of ice margins and relative sea level have been studied over a long time, exact data on the spatial distribution of Neoglacial changes of glacier load and relative sea level are still sparse. Present information points to a major conversion from emergence to submergence between 1000 and 3000 B.P., depending on location and the effect of superimposed secondary oscillations.
Review of the Survey's activities in 1993 - new discoveries and perspectives
Authors: Ghisler M
Published: June 2021

In general 1993 was a very encouraging year for GGU. The most exciting geological developments were the find of a major zinc deposit in North Greenland by the Canadian company Platinova A/S and the further investigations of the live oil showing discovered in 1992 on Nuussuaq in West Greenland. Both discoveries have contributed to increased interest in exploration for mineral resources by international oil and mining companies in Greenland.
Meeting the role of a modern geological survey: GGU's publication and data service
Authors: Dawes P.R
Published: June 2021

Who are we? What are our aims? What can we do? What can we do for you? Today questions like these underlie much of the profile material presented by national and provincial geological surveys the world over. More than ever before, geological surveys are involved with self-assessment to ensure that their work areas are relevant to the needs of industry. There is increased effort to provide the geological maps and the metallogenic and hydrocarbon models that industry needs. The modem outlook is for geological surveys to encourage private-sector exploration by pin-pointing new areas with promising economic potential.
Mineral resource activities 1993: spectrum of research and services
Authors: Schønwandt H.K
Published: June 2021

The Geological Survey of Greenland (GGu) has over the past few years improved its service to the mineral industry, not only by streamlining access to basic geological, geophysical and geochemical data, but also by increased effort in informing the mineral industry about available geodata. In recent issues of Report of Activities several papers discuss the nature of relevant geodata (Schønwandt 1990, 1993). and Dawes (this report) has summarised GGU's data service in its present form.
Archaean and early Proterozoic basement provinces in Greenland
Authors: Kalsbeek F
Published: June 2021

Information about the age and plate-tectonic setting of Precambrian basement terrains is of major importance for the evaluation of their mineral potential. The Geological Survey of Greenland (GGU) has therefore over the last two decades collected and published geochronological information on Greenland basement areas, based on whole rock Rb-Sr, Pb-Pb, Sm-Nd and zircon U-Pb isotope data. These isotope data, together with other geochemical information, also yield important clues for the plate-tectonic setting of the investigated terrains. GGU does not have laboratory facilities for isotope work, and most studies were therefore carried out in cooperation with university scientists from Denmark and abroad. This effort has led to the recognition of a number of distinct Precambrian basement provinces. A broad outline of results is given below.
The geology of the north-eastern corner of Greenland - photogeological studies and 1993 field work
Authors: Jepsen H.F , Escher J.C , Friderichsen J.D , Higgins A.K
Published: June 2021

Late Archaean and Early Proterozoic crust-forming events in North-East and eastern North Greenland were succeeded by Middle Proterozoic sedimentation and volcanic activity; Late Proterozoic through Tertiary sedimentation was interrupted by several periods of tectonic activity, including the Caledonian orogeny in East Greenland and the Mesozoic deformation of the Wandel Hav mobile belt. Photogeological studies helped pinpoint areas of special interest which were investigated during the short 1993 field season. Insights gained during field work include: the nature of the crystalline basement terrain in the Caledonian fold belt, redefinition of the upper boundary of the Upper Proterozoic Rivieradal sandstones, revision of Caledonian nappe terminology, and the northern extension of the Caledonian Storstrømmen shear zone.
Gneiss complex of the Skærfjorden region (76°-78°N), North-East Greenland
Authors: Hull J.M , Friderichsen J.D , Gilotti J.A , Henriksen N , Higgins A.K , Kalsbeek F
Published: June 2021

The crystalline rocks of the Skærfjorden region are dominated by grey migmatitic orthogneisses with smaller bodies of ultramafic, mafic and metasedimentary lithologies. Archaean rocks (c. 3.0 Ga) have been documented, but crustal additions were predominantly Early Proterozoic (2.0–1.75 Ga) in age, reflecting subduction zone magmatism. FolIowing Early Proterozoic orogenesis and migmatisation, granitic sheets (c. 1.7 Ga) and dolerite dykes were intruded. These intrusive rocks were subsequently deformed and metamorphosed in the Caledonian orogeny (c. 400 Ma). The Skærfjorden region is located in the Caledonian hinterland, where orogen parallel stretching and extension followed an early nappe stage.
Lead isotope signatures of mineralised rocks in the Caledonian fold belt of North-East Greenland
Authors: Jensen S.M
Published: June 2021

Lead isotope analyses of samples with small accumulations of metals and incompatible elements from the Precambrian gneisses of North-East Greenland indicate that mineralisation mostly involved remobilisation of metals from local host rocks. Source ages of Iead fall in three groups: (I) 1700–2400 Ma for Lower Proterozoic skarns, Caledonian sulphide-bearing pegmatites and quartz veins, and post-Jurassic pyrite-mineralised fault breccias; (2) 900–1000 Ma for Caledonian shear zones and Caledonian(?) skarns in Middle-Late Proterozoic rocks; and (3) ~400 Ma for Caledonian thrust zones with associated relative uranium enrichment along thrust planes.
Rock magnetism of Tertiary volcanics from North-East Greenland
Authors: Abrahamsen N , Nordgerd P
Published: June 2021

Rock magnetic results from 8 profiles covering stratigraphically the northern part of the Early Tertiary volcanic province in North-East Greenland (73°30'-75°N) are summarised. Tests in the field revealed only reversed polarities, which are likely to fall in the time span between chron 24r and 26r. Mean magnetic susceptibilities from 60 sites (some 2100 in situ measurements), together with average values of the intensity of the NRM (based upon 160 samples from 37 flows and dykes) and corresponding Q ratios, are tabulated. The overall means and standard deviations are k = 0.010 SI (s.d. = 0.003), J = l.7 Atm (s.d. = l.3) and Q= 2.8 (s.d. = 3), respectively. The susceptibilities are normally distributed, in contrast to the NRM intensity values and the Q ratios, which tend to be log-normal distributed.
Nye perspektiver for grønlandsarbejdet
Authors: Ghisler M
Published: June 2021

No abstract available.
Not just a pretty picture: the database behind GGU's Thematic Map Series
Authors: Ady B
Published: June 2021

One of the tasks of a modern geological survey is to build the geoscientific databases on which exploration companies make decisions, thus confronting them with data handling problems which involve many different types of complex spatial data. Geoscience data, characterised as it is by its large volume, variable nature, inherent uncertainty and lack of completeness has always presented challenges. These challenges are particularly acute when a demanding client base requires and expects access to this data in digital form and in standard formats. The Geological Survey of Greenland's (GGU) own mandate to provide industry with data has been previously described (Ghisler 1990: Dawes 1994) and the importance of GGU's data­base and the benefits of Greenland's unique 'underexplored/good geodata base’ duality has been discussed by Dawes (1994). A tangible result of GGU's attempt to deliver data from its databases to external clients has been in the Thematic Map Series, first published in 1990 as one of several new initiatives aimed at increasing interest in mineral exploration in Greenland.
Environmental impact on Greenland glaciers
Authors: Olesen O.B , Weidick A , Reeh N , Thomsen H.H , Braithwaite R.J
Published: June 2021

The main emphasis of present investigations of Greenland glaciers concerns former climate oscillations and the variations in glacier cover related to these changes. The data acquired on climate and glacier variations provide a basis for prediction of future environmental consequences of climate changes. These include local change of ice cover and related coastal changes caused by variations in glacier load on the earth's crust in Greenland as well as global change of sea level in the oceans caused by the storage or release of melt water and calf ice from the Greenland ice cover.
Råstofkortlægning. Erfaringer fra en forsøgskortlægning ved Ålborg
Authors: Stenestad Erik
Published: June 2021

The Geological Survey of Denmark (DGU) may be placed in a central position in future mapping of geological raw materials. For this reason, a pilot mapping project was carried out during October 1975. This paper is a presentation of a possible procedure, based on experience from the pilot project. It is suggested that resource planning is accomplished in six steps, the first of which is a synthesis of known data, presented as maps showing potential resources. The mapping method is described in detail and illustrated by examples from the pilot project. Three categories of maps are considered: A - Maps from previous investigations showing basic geological data (A 1) and special features, e.g. the Pre-Pleistocene surface (A 2), geophysical interpretations (A 3), groundwater chemistry (A 4) and contour lines of groundwater level (A 5) etc. B - Maps representing compilations and interpretations which are indispensable for the preparation of the resource maps, e.g. maps of surface lithology (B 1), quarries, pits and borings except waterwells (B 2), terrain morphology (B 3), terrain analysis (B 4) and maps showing the known distribution of raw materials (B 5a: Clay, B 5b: Sand and gravel, B Se: Limestone, etc.) C - Resource maps giving the concluding geological evaluation of all areas. The preliminary maps indicate the location of potential resources. It is not intended to give any evaluation of their quality or utility, since the criteria on which such judgments have to be based are highly variable depending on production techniques, market price etc. Finally, an outline is presented showing how detailed plans for production and supply may be developed by subsequent planning and additional investigations.
Megaspore assemblages from the Jurassic and lowermost Cretaceous of Bornholm, Denmark
Authors: Koppelhus Eva Bundgaard , Batten David John
Published: June 2021

There are more than 600 slides containing megaspores in "Helge Gry's collection", housed at the Geological Survey of Denmark in Copenhagen. The majority of the specimens are unnamed, all are from the Danish island of Bornholm in the Baltic Sea, and none has been described hitherto. The stratigraphic distribution of 22 of the taxa was, however, taken into account in a paper by Gry, published in 1969, and 16 of these were illustrated by small line drawings. He considered the lithology, areal extent and depositional history of what were thought at the time to be only Jurassic strata on Bornholm. The youngest part of the succession he discussed, the "Purbeck beds" (Rabekke and Robbedale Formations), are, however, now known to be mainly, if not entirely, of earliest Cretaceous age. In the present paper Gry's megaspore records are brought up to date so that they can be used more effectively along with other microfossils in drawing biostratigraphical and palaeoenvironmental conclusions. All 22 taxa to which he referred are discussed and illustrated, mostly with scanning electron micrographs, and their nomenclature emended where necessary. Descriptions and figures of an additional 15 forms encountered in the collection are included. Three of these arc new species of megaspores and one is a palynomorph of uncertain origin, named Henrisporites bornholmensis, Paxillitriletes kristinae, P. rasmusii and Aneuletes discus respectively. Most, if not all, of the megaspores in Gry's collection are likely to have selagincllalean or isoetalcan affinities. There is no evidence of the presence of heterosporous water ferns. The assemblages differ significantly in composition according to their relative ages, with several forms being of considerable biostratigraphic value. There is, however, still room for greater precision in determining local stratigraphic ranges, and also a need to apply occurrence data to palaeoenvironmental interpretations. This will require carefully documented collecting of new samples.
Depositional environments of coal and associated siliciclastic sediments in the Lower and Middle Jurassic of Denmark. The Øresund -5, -7, -13, -15 and -18 wells
Authors: Petersen Henrik Ingermann
Published: June 2021

Five cored wells located in the Fennoscandian Border Zone in the Øresund area, Denmark, encountered Lower or Middle Jurassic coal-bearing strata; the coal seams are Lignite to Sub-bituminous A/High Vol. Bituminous C in rank. A number of shallowing-upward units are recognized in the five wells. Each unit is capped by a coal seam. Correlation of these shallowing-upward units between wells is difficult on the basis of available biostratigraphy and log data. Seven of the coal seams result from establishment of peatforming conditions due to infilling of freshwater lakes, whereas the last two of the coal seams result from peat accumulation on top of restricted brackish lagoon or bay sediments. However, only one of the latter two seams accumulated in an environment influenced by saline water. Hence, the investigated coals represent almost entirely freshwater peat-forming environments. Three main types of environments are defined: 1) Type 1 is a sparsely vegetated open water swamp; it is represented by a limnic facies. The deposit is typically a carbonaceous claystone with a high content of allochthonous organic matter; 2) Type 2 is a densely vegetated rheotrophic, nutrient-rich and anoxic swamp; it is represented by a limnotelmatic to telmatic facies. The coal has a very high content of humified organic matter; 3) Type 3, subdivided into the types 3a and 3b, is the driest environment of the three types. Type 3a is a desiccated ombrotrophic raised bog represented by a terrestrial facies. It is strongly influenced by a fluctuating watertable. The coals contain a high content of inertinite that generally shows a low reflectance. Type 3b is a mesotrophic to ombrotrophic domed bog; the environment alternates between dry oxidizing conditions and wet conditions. It is represented by a telmatic to terrestrial facies. In general, the three types of environments form ecosystems characterized by the groundwater influence, nutrient supply, and vegetation. Successions representing the hydrological evolution towards drier conditions due to vertical peat accretion are recognized in some of the seams. The vegetation was small-statured and consisted of a prominent herbaceous type of flora, shrub-like plants, smaller arboreous plants and, to a lesser extent, larger plants.
Geologi på Mols. Rapport udarbejdet for Fredningsplanudvalget for Århus amt
Authors: Rasmussen H. Wienberg
Published: June 2021

The geology of the Mols Bjerge peninsula and landscapes in the southern part of Djursland are reviewed on a basis of published information and new observations. A map of the prequaternary formations, a soil map and a geomorphological map of the area are presented. Numerous inclusions of Lower Eocene clay in the ground morain indicate that the Lower Eocene (Ypresian) constitutes the Prequaternary surface of the Mols Bjerge peninsula and areas north of Kalø Vig. Prominent hills and ridges of glaciofluvial sand along the East Jutland ice margin and in Mols Bjerge were previously interpreted as push moraines in front of an ice advancing from the south. They are now interpreted as more or less undisturbed sediments deposited by meltwater in marginal and interlobate areas covered by remains of stagnant ice during the gradual retreat of the ice shield from East Jutland. They appear not to have been transported or pushed in any significant way by the ice.
Ostracoda of the Holsteinian Interglacial in Jutland, Denmark
Authors: Penney David Norman
Published: June 2021

Ostracoda are described from several marine Holsteinian deposits in Jutland, Denmark. The faunas are extremely uniform all over Jutland. Very little difference is seen between them and the faunas present in Late Elsterian deposits of the same area. They are largely boreal in aspect but contain a few species from warmer realms. With the exception of Callistocythere sp and Semicytherura sp, all the species are extant, though Carinocythereis whitei and Pterygocythereis coronata do not live in Danish inshore waters today. The environment at all the investigated localities was one of open, shallow waters (10-30 m depth) and normal marine salinities. No shallower water facies have as yet been identified. The Holsteinian ostracod faunas of Denmark are analogous to those recorded in North Germany, and show similarities to those reported from Mid-Pleistocene deposits in Great Britain.
Geochemistry of the Upper Permian Ca-2 Deposits of the Løgumkloster-1 Well, South Denmark
Authors: Stentoft Niels , Frykman Peter , Andersen Povl Valdemar , Rasmussen Kaare Lund
Published: June 2021

Rock samples of the Upper Permian Ca-2 unit of the Løgumkloster-l well have been subjected to chemical analysis. The Ca-2 interval was undoubtedly originally an aragonite which have undergone several episodes of diagenesis including a dolomitization and a heavy anhydrite mineralization. Two original facies types are recognized, an oolitic shoal facies, and a lagoonal carbonate facies. The samples have been characterized by neutron activation, atomic absorption, Xray diffraction, palaeomagnetism, optical and electron microscopical examination. Samples of the drilling mud has been analyzed as well, and it is found that contamination of the samples included in the present study from the drilling mud is unlikely to have happened. Imprints of both the original facies and the diagenetic events are found in the present work. The Sr and Ba abundances reflect the original facies-bound distribution, which is also reflected in the normalized REE distribution patterns. A low-Sr anhydrite component is clearly distinguishable in several parameter cross plots. Iron, Sc, REE and several other elements are found to be situated in the EDTA-insoluble residue, which has been identified primarily as a muscovite or clay mineral phase. Pyrite is present, although of small relative volume it is thought to be responsible for the occurrence of As, Sb, and possibly Se. A small fraction of the Cr, As, and Sb may originate from the heavy part of the crude oil, the introduction of which was the last process of alteration the rock experienced. A geomagnetically reversed period is encountered in the middle of the Ca-2 interval, and is tentatively identified as one of the Tatarian reversed events.