scholarly journals Stratigraphy and Structure in East Spatsizi map area, North-Central British Columbia

1989 ◽  
Author(s):  
C A Evenchick
Keyword(s):  
British Columbia ◽  
North Central ◽  
Area North

Lower to Middle Jurassic (Pliensbachian to Bajocian) stratigraphy of the northern Spatsizi area, north-central British Columbia

1986 ◽  
Vol 23 (12) ◽  
pp. 1963-1973 ◽  
Author(s):  
Robert C. Thomson ◽  
Paul L. Smith ◽  
Howard W. Tipper
Keyword(s):  
British Columbia ◽  
Grain Size ◽  
Middle Jurassic ◽  
Water Environment ◽  
Upper Jurassic ◽  
Calc Alkaline ◽  
Volcanic Arc ◽  
North Central ◽  
Area North ◽  
Southern Flank

The Lower to Middle Jurassic (Pliensbachian to lower Bajocian) Spatsizi Group in the northern Spatsizi area of north-central British Columbia is formally defined and subdivided into the Joan, Wolf Den, Melisson, Abou, and Quock formations. Each formation reflects deposition in a different, dominantly fine-clastic environment with a varying input of volcanic (epiclastic or pyroclastic) detritus. The Spatsizi Group represents the basinward sedimentary equivalent of the coeval Cold Fish Volcanics, a group of calc-alkaline flows and breccias that accumulated in a volcanic arc along the southern flank of the Stikine Arch. Arc-to basin-facies trends are best developed in the Joan and Wolf Den formations and are characterized by a decrease in the volcaniclastic component of the sediments, an overall reduction in grain size, and a progressively deeper water environment of deposition, as inferred from both sedimentological and faunal evidence.In the study area, the Spatsizi Group underlies with a slight angular discordance the Middle to Upper Jurassic Bowser Lake Group. Bowser lake sediments were deposited in the Bowser Basin, the largest Mesozoic successor basin in British Columbia. Based on evidence from the Spatsizi area and from other areas to the south at Diagonal Mountain and the Oweegee Mountains, the Spatsizi Group is interpreted as passing laterally into shales that underlie most of the Bowser Basin.

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