scholarly journals Field relations of some Precambrian basic dykes in the vicinity of Sukkertoppen, central West Greenland

1978 ◽  
Vol 90 ◽  
pp. 54-57
Author(s):  
C.R.L Friend
Keyword(s):  
Central Portion ◽  
Garnet Amphibolite ◽  
Basic Dyke ◽  
West Greenland ◽  
Dyke Swarms

Various field relations of the basic dyke swarms near Sukkertoppen have been described (Ramberg, 1948; Berthelsen & Bridgwater, 1960; Windley, 1970) and a preliminary chronology suggested (Bridgwater et al., 1976). The Kangâmiut dykes are noteable in that the central portion of some of the dykes has been converted into amphibolite and garnet amphibolite (Ramberg, 1948; Windley, 1970). Otherwise they appear as normal dolerites.

scholarly journals Ti-rich plagioclase-phyric dykes of southern West Greenland

1987 ◽  
Vol 135 ◽  
pp. 46-52
Author(s):  
R.P Hall ◽  
D.J Hughes ◽  
C.R.L Friend
Keyword(s):  
World Wide ◽  
Entire Region ◽  
Basic Dyke ◽  
Systematic Mapping ◽  
Late Archaean ◽  
West Greenland ◽  
Mantle Evolution ◽  
The World ◽  
Geological Map ◽  
Dyke Swarms

The investigation of Proterozoic basic dykes in southern West Greenland stemmed from the programme of systematic mapping of the Archaean craton in that region by the Geological Survey of Greenland (GGU). This work began in the southern Frederikshåb region in the early 1960s (Jensen, 1968, 1969) and progressed northwards, from bases in the Fiskenæsset (Kalsbeek & Myers, 1973; GGU, 1976), Godthåb (Allaart et al., 1977) and Sukkertoppen areas (Allaart et al., 1978). The results of most of this mapping work were summarized by Bridgwater et al. (1976) and compiled onto a 1:500 000 scale geological map sheet by Allaart (1982). The distribution of the major Proterozoic dykes which cut the entire region is shown on this map. While the basic dykes are individually minor intrusions, many are up to 50 metres wide and continuous for several tens of kilometres, and collectively they represent a major magmatic event. As many of the Archaean terrains of the world possess Proterozoic basic dyke swarms, their compositions are crucial to a correlation of events from one craton to another and to an understanding of crustal and mantle evolution after the world-wide late Archaean sialic crust-forming event.

scholarly journals A metamorphosed basic dyke swarm in the vicinity of Sarqarigsup nunâ (Ravns Storø area), Fiskenæsset, southern West Greenland

1976 ◽  
Vol 73 ◽  
pp. 22-30
Author(s):  
C.R.L Friend
Keyword(s):  
Significant Part ◽  
Dyke Swarm ◽  
Basic Dyke ◽  
West Greenland ◽  
Plutonic Rocks ◽  
Dyke Swarms

Ancient dyke swarms have been used successfully as time markers throughout the Archaean of West Greenland, particularly in subdividing the early Archaean in the Godthåb region (McGregor, 1973). This paper describes a swarm of metamorphosed basic dykes which cut across the lithologicallayering and an early tectonic fabric in the Ravns Storø group of metavo1canic and plutonic rocks. Previously only sporadic occurrences of metamorphosed basic dykes have been noted in the Fiskenæsset region. The Sarqarigsup nuna swarm may thus have a significant part to play in the division of the events which have taken place in the area from the Frederikshåbs Isblink to Bjørnesund and perhaps even further north.

scholarly journals Remanent magnetic directions of some dykes from southern West Greenland

1966 ◽  
Vol 11 ◽  
pp. 36-37
Author(s):  
D.H Tarling
Keyword(s):  
The Other ◽  
West Greenland ◽  
Oriented Samples ◽  
Different Ages ◽  
Dyke Swarms

During the summer of 1965 Survey geologists collected 57 oriented samples from 25 dykes for palaeomagnetic investigations. The main problem was to see if palaeomagnetic methods could be used to distinguish dyke swarms of different ages. Of the 25 dykes, two were thought to be "Trap Diabase" (TD) dykes of late Phanerozoic age and seven dykes were thought to be Gardar in age (ca. 1100 m.y.); the other dykes were all of uncertain age.

The basic dyke swarms in the Wudang block and its geological significance

1998 ◽  
Vol 43 (13) ◽  
pp. 1111-1115 ◽  
Author(s):  
Dingwu Zhou ◽  
Chengli Zhang ◽  
Juli Wang ◽  
Liang Liu ◽  
Yunpeng Dong ◽  
...  
Keyword(s):  
Basic Dyke ◽  
Geological Significance ◽  
Wudang Block ◽  
Dyke Swarms

scholarly journals Geological reconnaissance of the Precambrian rocks of south-east Greenland

1969 ◽  
Vol 19 ◽  
pp. 43-50
Author(s):  
D Bridgwater ◽  
K Gormsen
Keyword(s):  
Structural Units ◽  
Basic Dyke ◽  
East Greenland ◽  
Precambrian Rocks ◽  
Central Block ◽  
Dyke Swarms

The Precambrian of SE Greenland can be divided into three main structural units; a northern block affected by the eastern continuation of the Nagssugtoqidian orogeny; a southern block affected by the Ketilidian orogeny; and a central block of gneisses unaffected by these younger events. The boundaries of the younger orogenies can be seen in the field by their effect on basic dyke swarms intruded into the older basement. With the exception of younger intrusive complexes, the rocks so far mapped within the two younger orogenic complexes in this part of Greenland are all derived from an older basement.

Earth’s oldest well-preserved mafic dyke swarms in the vicinity of the Isua greenstone belt, southern West Greenland

2000 ◽  
pp. 65-72 ◽  
Author(s):  
Rosalind V. White ◽  
James L. Crowley ◽  
John S. Myers
Keyword(s):  
Greenstone Belt ◽  
Current Knowledge ◽  
Field Work ◽  
Mafic Dyke ◽  
Multidisciplinary Research ◽  
Original Series ◽  
West Greenland ◽  
Important Region ◽  
Field Investigations ◽  
Dyke Swarms

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: White, R. V., Crowley, J. L., & Myers, J. S. (2000). Earth’s oldest well-preserved mafic dyke swarms in the vicinity of the Isua greenstone belt, southern West Greenland. Geology of Greenland Survey Bulletin, 186, 65-72. https://doi.org/10.34194/ggub.v186.5217 _______________ The Isukasia region of southern West Greenland contains the Earth’s oldest known supracrustal rocks (the c. 3.8–3.7 Ga Isua greenstone belt: Appel et al. 1998) and well-preserved mafic dyke swarms (Inaluk and Tarssartôq dykes: Nutman et al. 1983). This report describes field investigations of the dykes carried out in 1999 as part of the Isua Multidisciplinary Research Project, and summarises current knowledge of the dykes. The project was initiated in 1997 with the aim of coordinating a detailed reinvestigation of this geologically important region. Fifteen members of the group were involved in field work in 1999 and this article represents only one aspect of the work.

Dating of the Ameralik dyke swarms of the Nuuk district, southern West Greenland: mafic intrusion events starting fromc. 3510 Ma

2004 ◽  
Vol 161 (3) ◽  
pp. 421-430 ◽  
Author(s):  
Allen P. Nutman ◽  
Clark R. L. Friend ◽  
VICKIE C. Bennett ◽  
VIC R. McGregor
Keyword(s):  
West Greenland ◽  
Mafic Intrusion ◽  
Dyke Swarms

The tectonic significance of some basic dyke swarms in the Canadian Superior Province with special reference to the geochemistry and paleomagnetism of the Mistassini swarm, Quebec, Canada

1986 ◽  
Vol 23 (2) ◽  
pp. 238-253 ◽  
Author(s):  
W. F. Fahrig ◽  
K. W. Christie ◽  
E. H. Chown ◽  
D. Janes ◽  
N. Machado
Keyword(s):  
Genetic Relationship ◽  
Early Stage ◽  
Tectonic Setting ◽  
Superior Province ◽  
Plate Boundaries ◽  
Basic Dyke ◽  
Tectonic Significance ◽  
Fold Belts ◽  
Opening And Closing ◽  
Dyke Swarms

The Mistassini dykes extend northwest from the Mistassini embayment and comprise both tholeiitic and komatiitic suites. They are probably > 2000 Ma old and yield two major paleomagnetic components. One of these, with a pole at 131°W, 13°S, is thought to be an overprint related to the Elsonian Disturbance 1400–1500 Ma ago. A very steeply down (and reversed) component may be primary and has a pole at 080°W, 50°N.These spacial, chemical, and age relationships between the Mistassini, Molson, Marathon, and Payne River dyke swarms and the Aphebian supracrustal fold belts on the perimeter of the Superior Province suggest a genetic relationship between the dyke swarms and the fold belts. The supracrustal belts are evidence of the opening and closing of oceans, and the dyke swarms are evidence of early-stage failed arms related to these openings. More rarely (for example, the Payne River dykes), early-stage dyke swarms are developed and preserved parallel to the edges of newly developed spreading plate boundaries. Presumably if a spreading episode stops, the dykes themselves may remain as the only evidence of that event. Probably all the world's great continental dyke swarms have the above-described tectonic setting, and the number and extent of dyke swarms during a geological epoch may be a measure of the number and vigour of spreading events.

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