scholarly journals Stratabound scheelite and stratiform tourmalinites in the Archaean Malene supracrustal rocks, southern West Greenland

1987 ◽  
Vol 156 ◽  
pp. 1-26
Author(s):  
P.W.U Appel ◽  
A.A Garde
Keyword(s):  
West Coast ◽  
Stream Sediment ◽  
Amphibolite Facies ◽  
The West ◽  
Late Archaean ◽  
Sea Floor ◽  
West Greenland ◽  
Sediment Sampling ◽  
Geological Map ◽  
Boron Complexes

The Malene supracrustal rocks form large enclaves in the late Archaean Nûk gneisses within an area of at least 36 000 km2 on the west coast of Greenland and have been repeatedly deformed and metamorphosed under amphibolite facies conditions. Stream sediment sampling has shown that scheelite occurs in the supracrustal enclaves throughout the area. It occurs stratabound in amphibolites, micaceous quartzites, siliceous cordierite-bearing metasediments and tourmalinites. A detailed geological map has been made of the central part of Store Malene mountain close to Nuuk. Banded metavolcanic Malene amphibolites and siliceous cordierite-bearing metasediments contain stratiform tourmalinites, often with appreciable scheelite, in addition to common accessory tourmaline. The tourmaiinites predate the earliest recognisable phase of deformation as well as prominent simple pegmatites. The tourmaline probably originated as primary sea floor precipitates, and the primary or diagenetic tourmaline crystals were later overgrown with tourmaline during metamorphism. The scheelite and tourmaline are probably syngenetic and of submarine exhalative origin, and boron complexes may have played a role in transporting tungsten in hot brines.

scholarly journals A new anorthosite/gabbro complex at Nûgssuaq, central West Greenland

1989 ◽  
Vol 145 ◽  
pp. 16-20
Author(s):  
A.A Garde ◽  
A Steenfelt
Keyword(s):  
Shear Zones ◽  
Field Work ◽  
Stream Sediment ◽  
Aerial Photographs ◽  
Geochemical Mapping ◽  
Considerable Part ◽  
West Greenland ◽  
Sediment Sampling ◽  
Geological Map

As part of the GGU activity in the Disko Bugt region, central West Greenland (Kalsbeek, 1989), the authors carried out helicopter-supported geological reconnaissance mapping and stream sediment sampling for geochemical mapping in the area between Jakobshavn Isfjord and Qarajaq Isfjord (fig. 1). A considerable part of the season was spent in the eastern part of the Nûgssuaq peninsula, partly to complete the stream sediment sampling initiated in 1986 (see Steenfelt, 1988) and also because previous geological field work in eastern Nûgssuaq was very limited. The existing geological map at a Rapp. Grønlands geol. Unders. 145. 16-20 (1989) scale of 1:500 000 covering Nûgssuaq is almost entirely based on interpretation of aerial photographs. During the field work large occurrences of hitherto unknown anorthosite/gabbro rocks and supracrustal sequences were discovered in the gneiss terrain. Both the anorthosite/gabbro and supracrustal units appear to be tectonically interleaved with strongly foliated, flat-Iying or shallowly south-dipping orthogneisses, which themselves contain numerous shear zones suggesting substantial subhorizontal movements.

scholarly journals New geological map of the Thule region, North-West Greenland

1992 ◽  
Vol 155 ◽  
pp. 42-47
Author(s):  
P.R Dawes
Keyword(s):  
West Coast ◽  
The West ◽  
West Greenland ◽  
North West ◽  
Geological Map ◽  
Map Series ◽  
Inland Ice

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.

scholarly journals Stream sediment sampling in the Atâ area, central West Greenland

1988 ◽  
Vol 140 ◽  
pp. 24-26
Author(s):  
P.W.U Appel ◽  
C Knudsen
Keyword(s):  
Close Correlation ◽  
Stream Sediments ◽  
Stream Sediment ◽  
Amphibolite Facies ◽  
Gold Content ◽  
Sediment Samples ◽  
Sediment Sampling ◽  
Gneiss Granite ◽  
Field Season ◽  
Granite Complex

In 1982 scheelite was identified in stream sediments in the: Nuuk/Godthåb area, about 600 km south of Atâ. Subsequentlya regional stream-sediment programme was carried out in the Nuuk area from 1982 to 1987 as a result of which scheelite was found to be quite abundant in the 3800 m.y. old Isukasia supracrustalrocks as well as in the 3300 to 3000 m.y. old Malene supracrustal sequence (Appel, 1988). It was also recognised that there is a close correlation between the number of scheelite grains and the gold content of the heavy mineral concentrates in the Nuuk area (Appel, 1988). In the Ata area (fig. 1) extensive outcrops of supracrustal rocks are found. In these supracrustals, which have been metamorphosed to greenschist and amphibolite facies, abundant sulphide-rich horizons are found, as well as sulphide-bearing breccia zones with appreciable gold contents (Knudsen et al., 1988). During the 1987 field season geological reconnaissance mapping was carried out in two of the supracrustal areas and the gneiss-granite complex enclosing the supracrustal rocks ·was investigated (Knudsen et al., 1988). A limited programme of stream-sediment sampling was carried out in the Atâ area, where stream sediment samples were collected in all the main streams draining the supracrustal rocks.

Geological Results of Four Expeditions to Ubekendt Ejland, West Greenland

ARCTIC ◽  
1958 ◽  
Vol 11 (4) ◽  
pp. 198 ◽  
Author(s):  
Harald I. Drever
Keyword(s):  
West Coast ◽  
Intrusive Complex ◽  
The South ◽  
The West ◽  
Pyroclastic Rocks ◽  
West Greenland ◽  
Lower Group ◽  
Made In

Outlines petrological discoveries made in 1938, 1939, 1950 and 1957 by British expeditions to this island in the Umanak Fjord region: an abundance of magnesia-and lime-rich intrusions and lavas; a central intrusive complex in the south where acid and basic magmas co-exist; and a suite of dykes, lavas, and pyroclastic rocks on the west coast. Status of research on problems raised by these findings is reported. Discussion is included of author's investigations in 1957 of the olivine-rich rocks in the lower group of lavas and the minor intrusions cutting them. Detailed information on variations in the intrusions and on their relationship with the lavas is presented.

scholarly journals Field work in central west Disko, 1979

1980 ◽  
Vol 100 ◽  
pp. 51-55
Author(s):  
A.K Pedersen ◽  
F Ulff-Møller
Keyword(s):  
West Coast ◽  
Field Work ◽  
The West ◽  
Field Investigations ◽  
Extensive Field ◽  
Geological Map

Field work in the summer 1979 was concentrated in the area between 69°45'N and 70°00'N from the west coast into central Disko (fig. 15). Transport facilities were provided by the GGU cutter J. F. Johnstrup and by a helicopter. Two field teams led by A.K.P. and F.U.-M. completed extensive field investigations which together with work reported by Pedersen (1977) and Ulff-Møller (1979) will enable a final photogrammetric compilation af the geological map sheet 69 V. 1 N to be made. A.K.P. studied the Vaigat Formation and the Nordfjord and Niaqussat members of the Maligât Formation. F.U.-M. studied the Rinks Dal member of the Maligât Formation and dyke intrusions with native iran bearing rocks contaminated by sediment.

scholarly journals Zinc mineralisation at Navarana Fjord, central North Greenland

1985 ◽  
Vol 126 ◽  
pp. 105-109
Author(s):  
U.H Jakobsen ◽  
A Steenfelt
Keyword(s):  
West Coast ◽  
Stream Sediment ◽  
The West ◽  
The Matrix ◽  
Tectonic Movements ◽  
North Greenland

A 5-7 m wide vein of calcite intersecting Cambrian dolomite at the west coast of Navarana Fjord contains a 1 m wide breccia zone in which massive sphalerite constitutes the matrix. The mineralisation is hydrothermal and related to tectonic movements. Bitumen occurs in the breccia zone and it is suggested that the zinc and the hydroearbons were transported together in the mineralising fluid. The sphalerite mineralisation is seen as one expression of a major zine mineralising event indieated by a reconnaissanee stream sediment survey.

scholarly journals Project Westmar, A shallow marine geophysical survey on the West Greenland continental shelf

1979 ◽  
Vol 87 ◽  
pp. 1-29
Author(s):  
C.P Brett ◽  
E.F.K Zarudzki
Keyword(s):  
Continental Shelf ◽  
Geophysical Survey ◽  
The West ◽  
Shallow Marine ◽  
Western Margin ◽  
Sea Floor ◽  
West Greenland ◽  
Maximum Water ◽  
Shelf Margin ◽  
Morphological Relationship

An extensive shallow geophysical survey has been carried out on the West Greenland continental shelf between 64° and 69°30'N. Preliminary interpretation of the data reveals that between 64° and 67°30'N at least, the entire shelf was glaciated to its western margin during the Pleistocene, the glaciation processes leaving a variable (< 20-200 m thick) cover on the Tertiary sedimentary wedge underlying the shelf. A morphological relationship exists between the degree of sea floor roughness and the types of glaciation forms. The distribution and contacts of the three main shallow bedrock units in the area (Precambrian gneisses, Lower Tertiary volcanics and Tertiary sediments) are delineated. Widespread prograding is observed in sediments along the shelf margin. Extensive iceberg scouring of the sea floor is observed north of 67°30'N reaching a maximum water depth of 340 m.

scholarly journals Geochemical prospecting at Mesters Vig, central East Greenland and at Mârmorilik, central West Greenland

1976 ◽  
Vol 80 ◽  
pp. 116-120
Author(s):  
H.R Cooke
Keyword(s):  
Heavy Metals ◽  
West Coast ◽  
Metal Content ◽  
East Coast ◽  
Mining District ◽  
The West ◽  
East Greenland ◽  
West Greenland ◽  
Geochemical Prospecting ◽  
Lead Zinc

A prospecting method used in 1975 in Greenland and reported briefly on here measures the total cold extractable amount of seven heavy metals, Zn, Pb, Cu, Co, Ni, Sn and Ag. The primary aim of the method is to discover and outline metal anomalies but not to determine their metal content accurateIy. Once an anomaly is targeted this can be done by more detailed foIlow-up surveys. The two areas chosen to test the suitability of the method to Greenland conditions, were the lead-zinc mining district of Mesters Vig on the east coast and the Sorte Engel (Black Angel) mine at MârmoriIik on the west coast. The traverses run show strong anomalies over kriown veins (figs 37 & 38, AA' & CC'; fig. 39, GG' & HH'), as well as indicatingpreviously unknown mineralisation (fig. 38, BB'; the western anomaly in fig. 39, HH').

Effects of Oceanic Variations and the West Greenland Fishery on Age at Maturity of Icelandic West Coast Stocks of Atlantic Salmon (Salmo salar)

1989 ◽  
Vol 46 (1) ◽  
pp. 16-27 ◽  
Author(s):  
Dennis L. Scarnecchia ◽  
Árni Ísaksson ◽  
S. E. White
Keyword(s):  
Time Series ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
West Coast ◽  
Strongly Correlated ◽  
The West ◽  
West Greenland ◽  
Atlantic Salmon Salmo Salar ◽  
The Mean ◽  
Salmon Fishery

Investigations were conducted on the effects of oceanic variations (as measured by sea temperatures) and catches by the West Greenland salmon fishery on the sea age composition of Atlantic salmon (Salmo salar) stocks from 21 Icelandic west coast rivers. Annual ratios of grilse to two-sea-winter (2SW) salmon were strongly correlated among the 21 rivers. All eight rivers with time series extending back before the expansion of the West Greenland fishery showed lower ratios during the earlier period. Only 2 of the 21 rivers, however, had significantly declining ratios over their time series. In addition, for only one river was West Greenland catch significantly related to the ratios (P < 0.05), and for only one river did ratios increase when the expanded West Greenland fishery was active. Overall, the effects of the fishery on stock composition are evidently minimal. The mean April–May temperature when the smolts were to migrate out of rivers was significantly and positively related to subsequent ratios for five of the rivers, which, along with correlations among the ratios, indicated that more rapid growth of smolts in their first summer may have increased the ratios of grilse to 2SW salmon on several rivers.

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