scholarly journals Precambrian crystalline basement at the head of Victoria Fjord, North Greenland

1985 ◽  
Vol 126 ◽  
pp. 11-16
Author(s):  
N Henriksen ◽  
H.F Jepsen
Keyword(s):  
Lower Cambrian ◽  
Small Area ◽  
Crystalline Rocks ◽  
Crystalline Basement ◽  
Amphibolite Facies ◽  
Isotopic Age ◽  
Late Proterozoic ◽  
Inland Ice ◽  
North Greenland ◽  
Age Determinations

Precambrian granites and gneisses outcrop below late Proterozoic and Lower Cambrian sediments in a small area at the margin of the Inland Ice. The exposed crystalline rocks comprise orthogneisses with scattered amphibolite bands, and occasional horizons of metasediments. The rocks are folded, somewhat migmatised and metamorphosed under amphibolite facies conditions. Samples for Rb-Sr whole rock and Zr isotopic age determinations have been collected.

scholarly journals K/Ar and Rb/Sr age determinations on Precambrian crystalline rocks in the Inglefield Land – Inglefield Bredning region, Thule district, western North Greenland

1974 ◽  
Vol 66 ◽  
pp. 5-8
Author(s):  
O Larsen ◽  
P.R Dawes
Keyword(s):  
Crystalline Rocks ◽  
Crystalline Basement ◽  
Basal Part ◽  
Age Dating ◽  
Basement Complex ◽  
Field Investigations ◽  
First Results ◽  
North Greenland ◽  
Selection Of ◽  
Age Determinations

FolIowing field investigations in North Greenland in 1971 by one of us (P.R.D.) a selection of rocks was made available for age dating work. The first results - K/Ar whole-rock ages on dolerites - suggest that the basal part of the unmetamorphosed Thule Group is at least 1200 m.y. old (Dawes et al., 1973). This note reports the first results of adating programme carried out by O. L. at the Institute for Petrology, Vniversity of Copenhagen and is concerned with the age of the underlying and older crystalline basement complex. Further work is continuing particularly on a Rb/Sr whole-rock isochron. Supplementary sample collecting is scheduled to take place in the summer of 1974.

scholarly journals Mapping in the Fiskefjord area, southern West Greenland

1982 ◽  
Vol 110 ◽  
pp. 55-57
Author(s):  
A.A Garde ◽  
V.R McGregor
Keyword(s):  
Granulite Facies ◽  
Amphibolite Facies ◽  
Isotopic Age ◽  
Supracrustal Rock ◽  
Granulite Facies Metamorphism ◽  
West Greenland ◽  
Facies Metamorphism ◽  
Geological Work ◽  
Age Determinations

Previous geological work on the 1:100000 map sheet 64 V.l N (fig. 15) includes published maps of smaller areas by Berthelsen (1960, 1962) and Lauerma (1964), mapping by Kryolitselskabet Øresund A/S (Bridgwater et al., 1976) and mapping by GGU geologists for the 1:500000 map sheet Frederikshåb Isblink - Søndre Strømfjord (Allaart et al., 1977, 1978). The Amltsoq and Niik gneisses and Malene supracrustal rock units south and east of Godthåbsfjord have not so far been correlated with rocks in the Fiskefjord area. Godthåbsfjord separates the granulite facies gneisses in Nordlandet from amphibolite facies Nûk gneisses on Sadelø and Bjørneøen; the granulite facies metamorphism occurred at about 2850 m.y. (Black et al., 1973), while no published isotopic age determinations from the Fiskefjord area itself are available.

Isotopic age determinations of crystalline rocks of the Upper Harz Mountains, Germany

1991 ◽  
Vol 80 (3) ◽  
pp. 669-690 ◽  
Author(s):  
Albrecht Baumann ◽  
Borwin Grauert ◽  
Sabine Mecklenburg ◽  
Roland Vinx
Keyword(s):  
Crystalline Rocks ◽  
Isotopic Age ◽  
Harz Mountains ◽  
Age Determinations

scholarly journals Late Proterozoic(?) to Silurian stratigraphy of southern Wulff Land, North Greenland

1979 ◽  
Vol 91 ◽  
pp. 37-56
Author(s):  
J.M Hurst ◽  
J.S Peel
Keyword(s):  
Crystalline Basement ◽  
Middle Ordovician ◽  
Late Proterozoic ◽  
Upper Silurian ◽  
North Greenland

Late Proterozoic(?) to Silurian clastic and carbonate sequences overlying crystalline basement in southern Wulff Land are described. Strata older than early Middle Ordovician compare best with the sequence to the east, in Peary Land, while late Middle Ordovician to Upper Silurian sediments show greater similarity to outcrops in western North Greenland.

scholarly journals Preliminary Rb-Sr isotope evidence on the age and metamorphic history of the North Greenland crystalline basement

1980 ◽  
Vol 99 ◽  
pp. 107-110
Author(s):  
F Kalsbeek ◽  
H.F Jepsen
Keyword(s):  
Crystalline Basement ◽  
Granitic Rocks ◽  
Sr Isotope ◽  
Metamorphic History ◽  
The North ◽  
Basement Rocks ◽  
History Of ◽  
Isotope Evidence ◽  
Inland Ice ◽  
North Greenland

No outcrops of crystalline basement rocks are known in the eastem part of North Greenland, mapped in 1978 and 1979 by the Geological Survey of Greenland. The oldest rocks are sandstones of the Proterozoic Independence Fjord Group (Collinson, this report). However, ice-transported boulders of gneisses, amphibolites and granitic rocks indicate the presence of crystalline rocks under the Inland Ice, perhaps not far south of the ice margin (fig. 46). The nearest outcrops of crystalline basement in North Greenland occur at the head of Victoria Fjord, c. 250 km west of Independence Fjord (Hurst & Peel, 1979). These rocks have as yet not been mapped or studied.

U–Pb age determinations on Proterozoic to Devonian rocks from northern Ellesmere Island, Arctic Canada

1987 ◽  
Vol 24 (2) ◽  
pp. 246-256 ◽  
Author(s):  
H. P. Trettin ◽  
R. Parrish ◽  
W. D. Loveridge
Keyword(s):  
Deep Water ◽  
Lower Cambrian ◽  
Crystalline Basement ◽  
Significant Component ◽  
Zircon Age ◽  
Water Basin ◽  
Middle Ordovician ◽  
Late Cambrian ◽  
Deep Water Basin ◽  
Age Determinations

This paper presents age determinations on six units of the Franklinian deep-water basin and the Pearya Terrane of northern Ellmere Island and discusses their tectonic implications.Four different fractions of detrital zircon from the Lower Cambrian Grant Land Formation of the deep-water basin all have average 207Pb/206Pb ages of 2.2–2.4 Ga, suggesting that the sediments were derived mainly from Aphebian–Archean parts of the Canadian Shield rather than from the Neohelikian crystalline basement of Pearya, as assumed earlier. The first evidence for Ordovician arc-type volcanism in the northern part of the deep-water basin is provided by a Llandeilo(?) zircon age of [Formula: see text] but the fault-bounded volcanic unit could be exotic.Four major stratigraphic successions are recognized in Pearya. Present zircon studies confirm that succession I has been affected by a 1.0–1.1 Ga orogeny, as inferred earlier by Sinha and Frisch from a Rb–Sr isochron. A zircon age of [Formula: see text] on a rhyolite demonstrates that succession II extended into the Late Cambrian or Early Ordovician.Granitic intrusions in the Pearya Terrane, at Cape Richards and Cape Woods, are, respectively, Middle Ordovician (463 ± 5 Ma) and Devonian (382 ± 18 Ma or, more likely, 390 ± 10 Ma) in age on the basis of combined zircon and sphene determinations. They are post-tectonic with regard to major deformations in the Middle Ordovician and Late Silurian. Both have a significant component of xenocrystic zircon, which appears to have been derived from succession I of Pearya on the basis of upper intercept ages.

scholarly journals New K/Ar age determinations from southern West Greenland

1969 ◽  
Vol 19 ◽  
pp. 68-71
Author(s):  
R.St.J Lambert ◽  
J.G Simons
Keyword(s):  
Granulite Facies ◽  
Amphibolite Facies ◽  
Isotopic Age ◽  
West Greenland ◽  
Gneiss Complex ◽  
Major Scale ◽  
Age Determinations

The following four samples are from the pre-Ketilidian/pre-Nagssugtoqidian central gneiss complex of west Greenland (Pulvertaft, 1968), in which there are several amphibolite facies linear belts with conformable greenschist layers that contrast on a major scale with the complexly folded granulite facies complexes (Windley, in press). The following dates together with those published by Armstrong (1963) and Larsen and Møller (1968) suggest that the linear belts have an isotopic age in the range 2410-2710 m. y., whilst the granulite facies complex in the Fiskenæsset region has an age of at least 3210 m. y. There was also plutonic activity in the period 1940-1820 m. y. expressed by a weak metamorphism in late supracrustal rocks only preserved within the Godthåb-Isua linear belt and in the pegmatites around the Qôrqut granite (Larsen and Møller, op. cit.).

scholarly journals Archaean age and Proterozoic metamorphic overprinting of the crystalline basement at Victoria Fjord, North Greenland

1987 ◽  
Vol 133 ◽  
pp. 159-168
Author(s):  
B.T Hansen ◽  
F Kalsbeek ◽  
P.M Holm
Keyword(s):  
Crystalline Rocks ◽  
Crystalline Basement ◽  
High Grade ◽  
Grade Metamorphism ◽  
Isotope Data ◽  
High Grade Metamorphism ◽  
Strong Disturbance ◽  
North Greenland

Zircon U-Pb and Rb-Sr whole-rock isotope data show that the crystalline rocks at the head of Victoria Fjord, North Greenland, have Archaean ages (c. 3000 Ma), but that strong disturbance of the isotope systems has taken place later. K-Ar analyses on hornblende show that the area underwent a phase of high-grade metamorphism during the Proterozoic, probably around 1850 Ma.

scholarly journals Paleomagnetic data and U-Pb isotopic age determinations from Coats Land, Antarctica: Implications for late Proterozoic plate reconstructions

1997 ◽  
Vol 102 (B4) ◽  
pp. 7887-7902 ◽  
Author(s):  
Wulf A. Gose ◽  
Mark A. Helper ◽  
James N. Connelly ◽  
Fred E. Hutson ◽  
Ian W. D. Dalziel
Keyword(s):  
Paleomagnetic Data ◽  
Isotopic Age ◽  
Late Proterozoic ◽  
Plate Reconstructions ◽  
Age Determinations
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