Superimposed Neoproterozoic and Early Tertiary alkaline magmatism in the La Biche River area, southeast Yukon Territory

2004 ◽  
Vol 52 (4) ◽  
pp. 325-342 ◽  
Author(s):  
L.C. Pigage
1975 ◽  
Vol 12 (11) ◽  
pp. 1910-1916 ◽  
Author(s):  
Colin I. Godwin

A small part of the Klotassin batholith, that intrudes the Yukon Metamorphic Complex, has been studied in detail near the Casino porphyry copper–molybdenum deposit, Yukon Territory. Eleven potassium–argon model ages, including concordant biotite and hornblende ages, indicate a mid-Cretaceous (100 Ma) age for this batholith. All ages are indistinguishable statistically. This age, therefore, is interpreted as the age of emplacement of the Klotassin batholith. Older dates can be expected from rocks of the Yukon Metamorphic Complex, the Carmacks batholith, and Aishihik batholith.The Casino complex, host to the Casino deposit, is dated at latest-Cretaceous (70 Ma), based on potassium–argon model ages from two samples of biotite. The complex is clearly intrusive into and younger than the Klotassin batholith. Previously, this unit was interpreted as Early Tertiary. Possibly the several so called Early Tertiary volcanic and hypabyssal rocks in Yukon are not strictly contemporaneous.


1993 ◽  
Vol 40 ◽  
pp. 280-287
Author(s):  
Troels F. D. Nielsen ◽  
Paul M. Holm

The Gardiner Complex formed during the early Tertiary opening of the North Atlantic. The complex is strongly alkaline and referred to a zone of alkaline flank magmatism 100 km west of the melting anomaly in the initial rift of the North Atlantic. Earlier investigations have documented that most rocks of the complex can be referred to three suites which are all suggested to have been formed from a single parental melanephelinitic liquid. The Nd and Sr isotope compositions presented here support this conclusion. Minor deviations are believed to be due to interaction with Archaean basement. The isotopic characteristics suggest that the alkaline magmatism originated in a source similar to that of the contemporaneous picritic and basaltic tholeiites. The isotopic composition of the source is Jess depleted than pervalent mantle (PREMA) and sets an upper enrichment limit to the composition of the Icelandic plume component 50 Ma ago.


1982 ◽  
Vol 19 (1) ◽  
pp. 8-22 ◽  
Author(s):  
James K. Mortensen

The central Pelly Mountains in southeastern Yukon Territory consist of imbricate thrust sheets, which have undergone syn- and post-thrusting deformation and metamorphism. The local geology is further complicated by the intrusion of Late Cretaceous batholiths, and by strike-slip faulting related to the Tintina Fault, a major northwest-trending transcurrent fault of latest Cretaceous or early Tertiary age. This faulting disrupts the northeast edge of the study area.Upper Devonian and Mississippian strata are present in at least two of the structural packages, but the Mississippian metavolcanic rocks occur only in the lowermost package. Rb–Sr geochronology indicates a mid-Mississippian age for the igneous suite. The volcanic rocks consist of volcaniclastic material with minor interbedded flows, and were deposited in a submarine environment. Several coeval and cogenetic syenite and trachyte domes and small stocks are the remains of vent areas. Although the volcanic rocks are all highly altered and show evidence of widespread chemical mobility, trace element data indicate that the rocks are metaluminous trachytes, most closely resembling peralkaline volcanics generated in extensional environments. This suggestion of a predominantly extensional tectonic setting in mid-Mississippian time in the Pelly Mountains is consistent with recent tectonic syntheses for the area.


1985 ◽  
Vol 22 (4) ◽  
pp. 525-537 ◽  
Author(s):  
Frederic H. Wilson ◽  
James G. Smith ◽  
Nora Shew

The results of more than 20 years of geochronological studies in the Yukon Crystalline Terrane in east-central Alaska and the western Yukon Territory suggest at least six igneous and thermal (metamorphic?) events. Plutonism during Mississippian, Early Jurassic, mid-Cretaceous, Late Cretaceous, and early Tertiary times is indicated. Evidence also indicates that Mississippian, Early Jurassic, late Early Cretaceous, and late Cretaceous thermal (metamorphic?) events have affected parts of the terrane. The western part of the terrane was affected by a significant regional metamorphic event in late Early Cretaceous time, followed by a terrane-wide mid-Cretaceous plutonic event. The pattern of K–Ar ages allows division of the terrane into domains, bounded by northeast-trending lineaments.


1972 ◽  
Vol 9 (7) ◽  
pp. 918-921 ◽  
Author(s):  
P. A. Christopher ◽  
W. H. White ◽  
J. E. Harakal

A 26 ± 0.3 m.y. mean age was determined for quartz latite porphyry near Burwash Creek, Yukon Territory. This apparent age for mineralized porphyry represents the youngest documented porphyry prospect in the Canadian Cordillera. Cretaceous ages determined for Kluane Range intrusions agree with geologic evidence, and early Tertiary ages from the Ruby Range batholith agree with a previous radiometric determination.


Author(s):  
Lars Stemmerik ◽  
Finn Dalhoff ◽  
Birgitte D. Larsen ◽  
Jens Lyck ◽  
Anders Mathiesen ◽  
...  

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Stemmerik, L., Dalhoff, F., Larsen, B. D., Lyck, J., Mathiesen, A., & Nilsson, I. (1998). Wandel Sea Basin, eastern North Greenland. Geology of Greenland Survey Bulletin, 180, 55-62. https://doi.org/10.34194/ggub.v180.5086 _______________ The Wandel Sea Basin in eastern North Greenland is the northernmost of a series of fault-bounded Late Palaeozoic – Early Tertiary basins exposed along the eastern and northern margin of Greenland (Fig. 1). The basin and the surrounding shelf areas are located in a geologically complex region at the junction between the N–S trending Caledonian fold belt in East Greenland and the E–W trending Ellesmerian fold belt in North Greenland, and along the zone of later, Tertiary, continental break-up. The Wandel Sea Basin started to develop during the Carboniferous as a result of extension and rifting between Greenland and Norway, and Greenland and Spitsbergen (Håkansson & Stemmerik 1989), and was an area of accumulation during the Early Carboniferous – Early Tertiary period. Two main epochs of basin evolution have been recognised during previous studies of the basin fill: an early (late Palaeozoic – early Triassic) epoch characterised by a fairly simple system of grabens and half-grabens, and a late (Mesozoic) epoch dominated by strike-slip movements (Håkansson & Stemmerik 1989). The Mesozoic epoch only influenced the northern part of the basin, north of the Trolle Land fault zone (Fig. 1). Thus the northern and southern parts of the basin have very different structural and depositional histories, and accordingly different thermal histories and hydrocarbon potential. This paper summarises the results of a project supported by Energy Research Program (EFP-94), the purpose of which was to model the Wandel Sea Basin with special emphasis on hydrocarbon potential and late uplift history, and to provide biostratigraphic and sedimentological data that could improve correlation with Svalbard and the Barents Sea. It is mainly based on material collected during field work in Holm Land and Amdrup Land in the south-eastern part of the Wandel Sea Basin during 1993–1995 with additional data from eastern Peary Land (Stemmerik et al. 1996). Petroleum related field studies have concentrated on detailed sedimentological and biostratigraphic studies of the Carboniferous–Permian Sortebakker, Kap Jungersen, Foldedal and Kim Fjelde Formations in Holm Land and Amdrup Land (Fig. 2; Døssing 1995; Stemmerik 1996; Stemmerik et al. 1997). They were supplemented by a structural study of northern Amdrup Land in order to improve the understanding of the eastward extension of the Trolle Land fault system and possibly predict its influence in the shelf areas (Stemmerik et al. 1995a; Larsen 1996). Furthermore, samples for thermal maturity analysis and biostratigraphy were collected from the Mesozoic of Kap Rigsdagen and the Tertiary of Prinsesse Thyra Ø (Fig. 1).


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