Devonian Plutonism in South-Central British Columbia

1975 ◽  
Vol 12 (10) ◽  
pp. 1760-1769 ◽  
Author(s):  
Andrew V. Okulitch ◽  
R. K. Wanless ◽  
W. D. Loveridge
Keyword(s):  
British Columbia ◽  
Middle Devonian ◽  
Metamorphic Complex ◽  
Western Margin ◽  
South Central ◽  
Minimum Age ◽  
History Of ◽  
Shuswap Metamorphic Complex

An apparently tabular body of granitoid gneiss, 3 to 5 km wide and more than 70 km long, that lies along the western margin of the Shuswap Metamorphic Complex between Shuswap and Admas Lakes, shows intrusive relationships with Palaeozoic and older rocks and has yielded zircons whose minimum age is 372 Ma. This intrusion, together with other granitoid plutons in the area that appear to be related to it, provide evidence of widespread plutonism during Middle Devonian time near the western edge of the Paleozoic Cordillera geosyncline and necessitate significant revisions in the interpretation of the crustal history of this region.

Stratigraphic revisions of the Nicola, Cache Creek, and Mount Ida Groups, based on conodont collections from the western margin of the Shuswap Metamorphic Complex, south-central British Columbia

1976 ◽  
Vol 13 (1) ◽  
pp. 44-53 ◽  
Author(s):  
A. V. Okulitch ◽  
B. E. B. Cameron
Keyword(s):  
British Columbia ◽  
Upper Triassic ◽  
Late Triassic ◽  
Metamorphic Complex ◽  
Western Margin ◽  
South Central ◽  
Western Border ◽  
Shuswap Metamorphic Complex

Conodonts have been recovered from highly deformed limestone and calcareous argillite in Palaeozoic and Mesozoic successions near the western border of the Shuswap Metamorphic Complex. Presently known biostratigraphic sequences indicate that the Eagle Bay Formation of the Mount Ida Group is in part Mississippian in age, and likely correlative with the Slide Mountain and Milford Groups. In addition, part of the succession previously mapped as Cache Creek Group in the Vernon area is now known to be Late Triassic in age, and can be correlated with the Sicamous Formation of the Mount Ida Group, the Nicola Group, and the Slocan Group. The Upper Triassic succession was affected by deformation and metamorphism associated with development of the Shuswap Metamorphic Complex.

Lithostratigraphic and tectonic framework of Jurassic and Cretaceous Intermontane sedimentary basins of south-central British Columbia1This article is one of a series of papers published in this Special Issue on the theme of New insights in Cordilleran Intermontane geoscience: reducing exploration risk in the mountain pine beetle-affected area, British Columbia.

2011 ◽  
Vol 48 (6) ◽  
pp. 870-896 ◽  
Author(s):  
Janet Riddell
Keyword(s):  
British Columbia ◽  
Mountain Pine Beetle ◽  
Sedimentary Basins ◽  
Hydrocarbon Exploration ◽  
South Central ◽  
Technological Advances ◽  
Exploration Risk ◽  
History Of ◽  
Geophysical Imaging ◽  
Glacial Cover

The south-central Intermontane belt of British Columbia has a complex architecture comprising late Paleozoic to Mesozoic volcanic and plutonic arc magmatic suites, marine and nonmarine clastic basins, high-grade metamorphic complexes, and accretionary rocks. Jurassic and Cretaceous clastic basins within this framework contain stratigraphy with hydrocarbon potential. The geology is complicated by Cretaceous to Eocene deformation, dismemberment, and dislocation. The Eocene to Neogene history of the southern Intermontane belt is dominated by non-arc volcanism, followed by Pleistocene to Recent glaciation. The volcanic and glacial cover makes this a difficult region to explore for resources. Much recent work has involved re-evaluating the challenges that the overlying volcanic cover has historically presented to geophysical imaging of the sedimentary rocks in this region in light of technological advances in geophysical data collection and analysis. This paper summarizes the lithological and stratigraphic framework of the region, with emphasis on description of the sedimentary units that have been the targets of hydrocarbon exploration.

The Great Tonalite Sill of southeastern Alaska and British Columbia: emplacement into an active contractional high angle reverse shear zone (extended abstract)

1992 ◽  
Vol 83 (1-2) ◽  
pp. 383-386 ◽  
Author(s):  
Donald H. W. Hutton ◽  
Gary M. Ingram
Keyword(s):  
British Columbia ◽  
Metamorphic Grade ◽  
High Grade ◽  
Metamorphic Complex ◽  
High Angle ◽  
Western Margin ◽  
Western Cordillera ◽  
Early Tertiary ◽  
The World ◽  
Gravina Belt

The Great Tonalite Sill (GTS) of southeastern Alaska and British Columbia (Brew & Ford 1981; Himmelberg et al. 1991) is one of the most remarkable intrusive bodies in the world: it extends for more than 800 km along strike and yet is only some 25 km or less in width. It consists of a belt of broadly tonalitic sheet-like plutons striking NW–SE and dipping steeply NE, and has been dated between 55 Ma and 81 Ma (J. L. Wooden, written communication to D. A. Brew, April 1990) (late Cretaceous to early Tertiary). The sill (it is steeply inclined and rather more like a “dyke”) is emplaced along the extreme western margin of the Coast Plutonic and Metamorphic Complex (CPMC), the high grade core of the Western Cordillera. The CPMC forms the western part of a group of tectonostratigraphic terranes including Stikine and Cache Creek, collectively known as the Intermontane Superterrane (Rubin et al. 1990). To the W of the GTS, rocks of the Insular Superterrane, including the Alexander and Wrangellia terranes and the Gravina belt, form generally lower metamorphic grade assemblages. The boundary between these two superterranes is obscure but it may lie close to, or be coincident with, the trace of the GTS.

Holocene history of earthflow mass movements in south-central British Columbia: the influence of hydroclimatic changes

1992 ◽  
Vol 29 (8) ◽  
pp. 1746-1755 ◽  
Author(s):  
Michael J. Bovis ◽  
Penny Jones
Keyword(s):  
British Columbia ◽  
Mass Movement ◽  
The Holocene ◽  
Wood Development ◽  
The Past ◽  
South Central ◽  
History Of ◽  
Changing Rate ◽  
Coherent Relationship ◽  
Past 300 Years

Large earthflows in south-central British Columbia have exhibited regionally consistent fluctuations in their movement during the Holocene. Over the past 60 years, air photographs show that many earthflows were reactivated during the relatively wet period 1950–1985. Over the past 300 years, a fairly coherent relationship is established between periods of wetter climate, defined by the tree-ring record, and phases of slope movement, defined by the record of compression-wood development in conifers located near earthflow headscarps. On a time scale of several thousand years, stratigraphic evidence shows that many large earthflows in the region underwent significant reactivation of movement in the post-Mazama period, during the relatively wet, cool Neoglacial interval of the Holocene. These lines of evidence indicate that Holocene hydroclimatic changes have exerted an important influence on the regimen of large earthflows. Earthflows present a wealth of paleogeomorphic information, hitherto largely neglected, that allows a reconstruction of the changing rate of mass movement with time.

Precambrian Zircon Age of Orthogneiss in the Shuswap Metamorphic Complex, British Columbia

1975 ◽  
Vol 12 (2) ◽  
pp. 326-332 ◽  
Author(s):  
R. K. Wanless ◽  
J. E. Reesor
Keyword(s):  
British Columbia ◽  
Metamorphic Complex ◽  
Gneiss Dome ◽  
Zircon Age ◽  
Core Zone ◽  
The Core ◽  
Basement Rocks ◽  
Proterozoic Basement ◽  
Shuswap Metamorphic Complex ◽  
Age Determinations

Pb-U age determinations carried out on zircon from granodiorite gneiss of the core zone of Thor-Odin gneiss dome have provided isotopic evidence for involvement of Proterozoic basement rocks in the Mesozoic structures of the Shuswap Metamorphic Complex. The study has revealed that the zircons originally crystallized [Formula: see text] ago and suffered an episodic loss of lead [Formula: see text] ago.

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