scholarly journals Reconnaissance for mineral occurrences in North-East Greenland (76°–78°N)

1994 ◽  
Vol 162 ◽  
pp. 163-168
Author(s):  
S.M Jensen ◽  
H Stendal
Keyword(s):  
Present Knowledge ◽  
Stream Sediment ◽  
Normal Faults ◽  
Fold Belt ◽  
East Greenland ◽  
Geochemical Anomalies ◽  
North East ◽  
Economic Significance ◽  
Incompatible Elements ◽  
Middle Proterozoic

Reconnaissance for indications of potentially economic mineralisation in the Caledonian fold belt of North-East Greenland has shown that stream sediment geochemical anomalies and mineral occurrences are related to Lower-Middle Proterozoic and Caledonian skarns, Caledonian shear and thrust zones, and breccias in post-Jurassic normal faults. None of the mineral showings are of economic significance. Mineralised rock samples, stream sediment silt samples and panned stream sediment heavy mineral concentrates generally have low contents of metals and incompatible elements, and only few areas stand out as being geochronically anomalous. On the basis of the present knowledge of the geology of the region the mineral potential is considered low.

scholarly journals Regional geology and 1:500 000 mapping in North-East Greenland

1990 ◽  
Vol 148 ◽  
pp. 16-20
Author(s):  
N Henriksen
Keyword(s):  
Geological Mapping ◽  
Fold Belt ◽  
East Greenland ◽  
Regional Geology ◽  
Field Mapping ◽  
North East ◽  
General Geology ◽  
Geological Map

A three-year field mapping programme was initiated in 1988 aiming at regional geological studies and geological mapping in North-East Greenland between latitudes 75° and 78°N. This region encompasses relatively little known parts of the Caledonian fold belt and the overlying post-Caledonian sequences, which lie north of the better known regions of central East Greenland (Henriksen, 1989). Major aims of the programme include compilation a 1:500 000 geological map, and an understanding of the general geology of the region.

scholarly journals The Krummedal supracrustal sequence around inner Nordvestfjord, Scoresby Sund, East Greenland

1974 ◽  
Vol 67 ◽  
pp. 1-34
Author(s):  
A.K Higgins
Keyword(s):  
Amphibolite Facies ◽  
Fold Belt ◽  
East Greenland ◽  
Facies Metamorphism ◽  
Sedimentary Succession ◽  
Middle Proterozoic

The Krummedal supracrustal sequence is a lower to middle Proterozoic sedimentary succession widely represented in the Caledonian fold belt of the Scoresby Sund region. Around inner Nordvestfjord laterally variable sequences of pelitic, semipelitic and psammitic rocks occur. The sequences of different areas ranging from 2500 m to more than 8000 m in thickness are described but no formal subdivision is attempted. High amphibolite facies metamorphism, migmatisation, emplacement of granite intrusions and several phases of deformation appear to relate to an orogenic episode giving dates in the range 900-1200 m.y. Caledonian orogenesis is represented by a relatively weak retrogressive metamorphic phase, westward displacements on major thrusts and emplacement of granite intrusions.

scholarly journals Search for Archaean basement in the Caledonian fold belt of North-East Greenland

1994 ◽  
Vol 162 ◽  
pp. 129-133
Author(s):  
A.P Nutman ◽  
F Kalsbeek
Keyword(s):  
High Grade ◽  
Metamorphic Zircon ◽  
Fold Belt ◽  
Pb Isotope ◽  
Zircon Age ◽  
East Greenland ◽  
Early Proterozoic ◽  
North East ◽  
History Of ◽  
High Grade Metamorphism

SHRIMP U-Pb isotope data on zircon crystals from a gneiss sample near Danmarkshavn, where the presence of Archaean rocks has earlier been documented, show that the rock has undergone a complex history of igneous and metamorphic zircon growth. At least three generations of zircon are present with ages of c. 3000 Ma, c. 2725 Ma and 1967 ±8 Ma (2 α). Apparently the rock was formed from an Archaean protolith which underwent high grade metamorphism during the early Proterozoic. Another sample from the easternmost exposures of the Caledonian basement, collected further north, yielded only early Proterozoic zircons with an age of 1963 ± 6 Ma. Together with a SHRIMP U-Pb zircon age of 1974 ± 17 Ma reported earlier, these results give evidence of a major igneous and metamorphic event in North-East Greenland about 1965 Ma ago.

Conclusion of the 1:500 000 mapping project in the Caledonian fold belt in North-East Greenland

1999 ◽  
pp. 10-22 ◽  
Author(s):  
Niels Henriksen
Keyword(s):  
Field Work ◽  
Fold Belt ◽  
East Greenland ◽  
Original Series ◽  
Preliminary Results ◽  
General Overview ◽  
North East ◽  
Review Articles ◽  
Field Season ◽  
Scientific Results

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Henriksen, N. (1999). Conclusion of the 1:500 000 mapping project in the Caledonian fold belt in North-East Greenland. Geology of Greenland Survey Bulletin, 183, 10-22. https://doi.org/10.34194/ggub.v183.5200 _______________ The second and last field season of the mapping project in the southern part of North-East Greenland (72°–75°N) was carried out in 1998 with full accomplishment of all planned goals. The general overview mapping of the East Greenland Caledonian fold belt has now been completed, in total covering a stretch of more than 1300 km between latitudes 70°N and c. 81°30´N (Fig. 1). The Survey’s systematic regional 1:500 000 mapping programme in the East Greenland Caledonides started with mapping in the Scoresby Sund region (70°–72°N) in 1968, and in the course of 13 field seasons spread over 30 years has involved more than 50 geologists for one or more field seasons each; several Survey geologists have participated in all 13 field seasons. The mapping of the Caledonian fold belt and the adjacent pre- and post-Caledonian rocks will be presented on five 1:500 000 map sheets of which three are already published and a fourth is under compilation. The scientific results are documented in numerous publications both in international journals and in the Survey’s own Bulletins and Reports. Review articles on various parts of the East Greenland Caledonian fold belt include those of Haller (1971), Henriksen & Higgins (1976), Higgins & Phillips (1979), Henriksen (1985, 1986), Hurst et al. (1985), Peel (1985), Peel & Sønderholm (1991), Higgins (1994) and Jepsen et al. (1994). Preliminary results of the 1997 and 1998 field work have been published in Survey reports (Higgins & Frederiksen 1998, 1999), and are summarised by Henriksen (1998) and in this article.

scholarly journals Age and origin of Caledonian granites in the Grandjean Fjord - Bessel Fjord region (75°–76°N), North-East Greenland

1994 ◽  
Vol 162 ◽  
pp. 139-151
Author(s):  
B.T Hansen ◽  
N Henriksen ◽  
F Kalsbeek
Keyword(s):  
Trace Element ◽  
East Greenland ◽  
Late Proterozoic ◽  
North East ◽  
Crustal Origin ◽  
Mixed Origin ◽  
Middle Proterozoic

The Grandjean Fjord – Bessel Fjord region (75°–76°N) contains the northernmost occurrences of Caledonian granites in North-East Greenland. Most of them have been emplaced along the margins of a sequence of late Proterozoic sediments, the Eleonore Bay Supergroup, or occur within middle Proterozoic metasediments of the Smallefjord sequence. Most granites are undeformed, but granite sheets within the Smallefjord sequence may be foliated. Zircon U-Pb dates indicate that they were emplaced about 400 Ma ago. Sm-Nd, Rb-Sr, and major and trace element analyses suggest that the granites are of mixed origin. Components of crustal origin and juvenile mantle-derived material are present, and occur in variable proportions. Under these circumstances precise dating of the rocks is difficult: Rb-Sr whole-rock errorchrons yield erroneous 'ages' and zircon U-Pb data are not always easily interpreted.

scholarly journals Progress report on geochronological investigations in the crystalline complexes of the East Greenland Caledonian fold belt between 72° and 74°N

1976 ◽  
Vol 80 ◽  
pp. 127-133
Author(s):  
D.C Rex ◽  
A.R Gledhill ◽  
A.K Higgins
Keyword(s):  
Progress Report ◽  
Geological History ◽  
Fold Belt ◽  
East Greenland ◽  
History Of ◽  
Crystalline Complexes Of ◽  
Middle Proterozoic

In the summer of 1974 two of the authors (D. C. R. & A. R. G.) collected samples from vanous crystalline units in the innerfjord region ofthe Caledonian fold belt between 72° and 74°N. with a view to testing current hypotheses of the geological history of the region. The only dates so far available from this region are a few K-Ar mineral ages reported by Haller & Kulp (1962) all of which reflect Caledonian orogenesis. In the Scoresby Sund region isotopic work on crystalline units comparable to some of those reported on here has yielded Archaean and middle Proterozoic as well as Caledonian ages (Hansen et al., 1973, 1974; Rex& Gledhill, 1974; Friderichsen & Higgins, this report).

scholarly journals Lead isotope signatures of mineralised rocks in the Caledonian fold belt of North-East Greenland

1994 ◽  
Vol 162 ◽  
pp. 169-176
Author(s):  
S.M Jensen
Keyword(s):  
Lead Isotope ◽  
Shear Zones ◽  
Uranium Enrichment ◽  
East Greenland ◽  
Quartz Veins ◽  
North East ◽  
Incompatible Elements ◽  
Local Host ◽  
Host Rocks ◽  
Isotope Analyses

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.

scholarly journals Sm-Nd model age of an early Proterozoic gabbro-anorthosite from the Caledonian fold belt in North-East Greenland

1994 ◽  
Vol 162 ◽  
pp. 135-137
Author(s):  
O Stecher ◽  
N Henriksen
Keyword(s):  
Fold Belt ◽  
Crust Formation ◽  
East Greenland ◽  
Early Proterozoic ◽  
North East ◽  
A Value ◽  
Nd Model Age

Metamorphosed anorthositic and gabbro-anorthositic rocks are found as scattered occurrences in the basement gneisses of the Caledonian fold belt of North-East Greenland. A Tm-MD-nd model age determined on a gabbro- anorthositic sample yields a value of 2146 Ma. This model age is in agreement with the general age of crust formation in the region. The result shows that anorthosites, which are of Archaean derivation in many areas in Greenland, cannot on their own be used as an indicator of Archaean crust.

scholarly journals Structure of the Storstrømmen shear zone, eastern Hertugen af Orléans Land, North-East Greenland

1994 ◽  
Vol 162 ◽  
pp. 103-112
Author(s):  
R.A Strachan ◽  
I.R Tribe
Keyword(s):  
Shear Zone ◽  
Greenschist Facies ◽  
Amphibolite Facies ◽  
Fold Belt ◽  
East Greenland ◽  
North East ◽  
Mineral Assemblages ◽  
Basement Gneiss

The Storstrømmen shear zone is a NNE-trending belt of steep, heterogeneously deformed gneisses and mylonites, at least 8 km wide, which transects the basement gneiss complexes of the Caledonian fold belt between Dronning Louise Land and Hertugen af Orleans Land. Shear criteria indicate a consistent sinistral sense of displacement parallel to a gently-plunging L-S fabric. Mineral assemblages and fabrics within the mylonites indicate that mylonitisation was initiated under low amphibolite facies conditions and continued within the greenschist facies. The shear zone is reworked by late, steep brittle faults which are associated with cataclasis and local metamorphic retrogression.

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