scholarly journals Archaean U-Pb zircon ages from the Scoresby Sund region, East Greenland

1987 ◽  
Vol 134 ◽  
pp. 19-24
Author(s):  
B.T Hansen ◽  
A.K Higgins ◽  
B Borchardt
Keyword(s):  
Fold Belt ◽  
East Greenland

U-Pb analyses on zircons are reported for two rock colleetions from infracrustal complexes within the East Greenland Caledonian fold belt in the Scoresby Sund region. Calculated minimum ages range from 2800 to 2965 Ma, and are the oldest ages obtained in the region using this method.

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.

Polyorogenic Nature of the Southern Caledonian Fold Belt in East Greenland: An Isotopic Age Study

1979 ◽  
Vol 87 (5) ◽  
pp. 475-495 ◽  
Author(s):  
R. H. Steiger ◽  
B. T. Hansen ◽  
Ch. Schuler ◽  
M. T. Bär ◽  
N. Henriksen
Keyword(s):  
Isotopic Age ◽  
Fold Belt ◽  
East Greenland

scholarly journals Isotopic evidence for a Precambrian metamorphic event within the Charcot Land window, East Greenland Caledonian fold belt

1981 ◽  
Vol 29 ◽  
pp. 151-160
Author(s):  
B. T. Hansen ◽  
R. H. Steiger ◽  
A. K. Higgins
Keyword(s):  
Regional Metamorphism ◽  
Metamorphic Event ◽  
Low Grade ◽  
Fold Belt ◽  
Thrust Sheet ◽  
East Greenland ◽  
Grade Metamorphism ◽  
Isotopic Evidence ◽  
Tectonic Window

Rb-Sr, U-Pb and K-Ar analyses on rocks and minerals from a tectonic window below a Caledonian thrust sheet in the westernmost part of the Scoresby Sund region (70°-72°N) give evidence for a Precambrian age of formation. The Charco't Land supracrustal sequence rests on a basement that is probably of Archaean development and older than at least 2100 m.y. The major regional metamorphism of the supracrustal rocks is probably not much older than the intrusion of two post-kinematic bodies, i.e. about 1840 m.y. Low-grade metamorphism in a tillite and low-grade retrogressive overprinting of the supra­crustal rocks are related to Caledonian orogenesis.

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 The geochronology of the Scoresby Sund area, central East Greenland

1974 ◽  
Vol 66 ◽  
pp. 32-38
Author(s):  
B.T Hansen ◽  
F Oberli ◽  
R.H Steiger
Keyword(s):  
Recent Work ◽  
Age Determination ◽  
Fold Belt ◽  
East Greenland ◽  
Rock Samples

The age determination programme on rocks from the Caledonian fold belt of East Greeniand has been continued at the Eidg. Technische Hochschule in Zürich. Recent work has been aimed at verification of the pre-Caledonian age for an early metamorphism of the Krummedal supracrustal sequence. Additional analyses on iurther rock samples of this sequence have clearly confirmed that a strong preCaledonian metamorphism affected the rocks of the Scoresby Sund area around 1000 to 1200 m.y. ago. This pre-Caledonian event is a1so reflected by the ages of three synkinematic granitic bodies in Nordvestfjord, Øfjord and on Bjørneøer.

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.

scholarly journals Precambrian Rb-Sr isochron ages from the crystalline complexes of inner Forsblads Fjord, East Greenland fold belt

1977 ◽  
Vol 85 ◽  
pp. 122-126
Author(s):  
D.C Rex ◽  
A.R Gledhill ◽  
A.K Higgins
Keyword(s):  
Standard Technique ◽  
Fold Belt ◽  
East Greenland ◽  
Crystalline Complexes Of ◽  
Proterozoic Age

Several collections of samples were made from crystalline units in inner Forsblads Fjord by D.C.R. and A.R.G. in 1974. Result of whole rock Rb-Sr analyes on two of these collections are presented here, and give an Archaean age for banded gneises and amiddle Proterozoic age for quartzitic metasediments. These ages confirm the occurrence of major Precambrian complexes within the East Greenland Caledonian fold belt (Hansen el al., 1973a, b, 1974; Rex & Gledhill, 1974; Rex el al., 1976; Henrik en & Higgins, 1976: Higgins 1976). Analyses were carried out using standard technique (Van Breemen & Dodson, 1972).

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.

Uranium and selected trace elements in granites from the Caledonides of East Greenland

1982 ◽  
Vol 46 (339) ◽  
pp. 201-210 ◽  
Author(s):  
Agnete Steenfelt
Keyword(s):  
Trace Elements ◽  
Heat Source ◽  
Iron Oxides ◽  
Hydrothermal Fluids ◽  
Fold Belt ◽  
Calc Alkaline ◽  
Alkaline Granite ◽  
Acid Magma ◽  
East Greenland ◽  
Secondary Enrichment

AbstractThe Caledonian fold belt of East Greenland contains calc-alkaline granite (sensu lato) intrusions with ages ranging from c.2000 Ma to c.350 Ma. The Proterozoic granites have low U contents and the pre-Devonian Caledonian granites contents of U corresponding to the clarke value for U in granites. Some aspects of the geochemistry of U are discussed using U-K/Rb, U-Sr, U-Zr, and U-Th diagrams. Secondary enrichment and mineralization occurs in fractured and hydrothermally altered granites and rhyolites situated in or near a major NNE fault zone. The U is associated with iron oxides or hydrocarbons. It is suggested that the source of the mineralization was Devonian acid magma, which also acted as a heat source for circulating hydrothermal fluids.

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