scholarly journals New correlations of the Hadrynian Windermere Supergroup in the northern Selkirk Mountains, British Columbia

1993 ◽  
Author(s):  
S E Grasby ◽  
R L Brown
Keyword(s):  
British Columbia ◽  
Windermere Supergroup ◽  
Selkirk Mountains

New correlations of Hadrynian strata, south-central British Columbia

1987 ◽  
Vol 24 (2) ◽  
pp. 302-313 ◽  
Author(s):  
J. Pell ◽  
P. S. Simony
Keyword(s):  
British Columbia ◽  
North America ◽  
Western North America ◽  
Late Proterozoic ◽  
South Central ◽  
Crustal Thinning ◽  
Windermere Supergroup ◽  
Selkirk Mountains ◽  
Lower Division

The Hadrynian (Late Proterozoic) Kaza Group is 3800 m thick in the southern Cariboo Mountains of south-central British Columbia, and it consists of a lower division of pelite and psammite (700 m), a middle division of granule conglomerate with thick pelite intervals and some quartzite and carbonate (1400 m), and an upper division of granule conglomerate with little pelite (1700 m). Contacts with both the overlying Isaac Formation of the Cariboo Group and with underlying marble, semipelite, and amphibolite are gradational. The underlying strata can be traced southeastward into the middle marble and the semipelite–amphibolite division of the Hadrynian Horsethief Creek Group. The upper clastic division that caps the Horsethief Creek Group in the Selkirk Mountains is a southeastward-thinning equivalent of the Kaza Group.Two southeastward-tapering wedges of granule conglomerate, pelite, and carbonate constitute the bulk of the Hadrynian Windermere Supergroup of southern British Columbia. The lower wedge is represented by the Horsethief Creek Group, exclusive of its upper clastic division. The upper wedge is represented by the upper clastic division, the Kaza Group, the overlying Cariboo Group, and the middle and upper Miette Group. The two wedges indicate two pulses of crustal thinning and stretching during Hadrynian rifting of western North America.

Ediacaran fossils and dubiofossils, Miette Group of Mount Fitzwilliam area, British Columbia

1991 ◽  
Vol 28 (10) ◽  
pp. 1541-1552 ◽  
Author(s):  
H. J. Hofmann ◽  
E. W. Mountjoy ◽  
M. W. Teitz
Keyword(s):  
British Columbia ◽  
Shallow Water ◽  
Rocky Mountains ◽  
Carbonate Mounds ◽  
Windermere Supergroup

Shallow-water clastic beds flanking stromatolitic carbonate mounds in the upper part of the Vendian Miette Group (Windermere Supergroup) of the Rocky Mountains contain a poorly preserved, soft-bodied fauna that comprises morphologically very variable discoid remains; these include the taxa Beltanella sp., cf. B. grandis, Charniodiscus? sp., Irridinitus? sp., Nimbia occlusa, Protodipleurosoma sp., cf. P. rugulosum, and Zolotytsia? sp. and seven types of dubiofossils.

The initiation of the early Paleozoic Cordilleran miogeocline: evidence from the uppermost Proterozoic – Lower Cambrian Hamill Group of southeastern British Columbia

1988 ◽  
Vol 25 (1) ◽  
pp. 1-19 ◽  
Author(s):  
William J. Devlin ◽  
Gerard C. Bond
Keyword(s):  
British Columbia ◽  
Lower Cambrian ◽  
Direct Evidence ◽  
Thermal Anomaly ◽  
Passive Margin ◽  
Early Paleozoic ◽  
Upper Proterozoic ◽  
Windermere Supergroup ◽  
Depositional Setting ◽  
Thermal Subsidence

The uppermost Proterozoic–Lower Cambrian Hamill Group of southeastern British Columbia contains geologic evidence for a phase of extensional tectonism that led directly to the onset of thermally controlled subsidence in the Cordilleran miogeocline. Moreover, the Hamill Group contains the sedimentological record of the passage of the ancient passive margin from unstable tectonic conditions associated with rifting and (or) the earliest phases of thermal subsidence to post-rift conditions characterized by stabilization of the margin and dissipation of the thermal anomaly generated during the rift phase (the rift to post-rift transition). Widespread uplift that occurred prior to and during the deposition of the lower Hamill Group is indicated by an unconformable relation with the underlying Windermere Supergroup and by stratigraphic relations between Middle and Upper Proterozoic strata and unconformably overlying upper Lower Cambrian quartz arenites (upper Hamill Group) in the southern borderlands of the Hamill basin. In addition, the coarse grain size, the feldspar content, the depositional setting, and the inferred provenance of the lower Hamill Group are all indicative of the activation of basement sources along the margins of the Hamill basin. Geologic relations within the Hamill Group that provide direct evidence for extensional tectonism include the occurrence of thick sequences of mafic metavolcanics and rapid vertical facies changes that are suggestive of syndepositional tectonism.Evidence of extensional tectonism in the Hamill Group directly supports inferences derived from tectonic subsidence analyses that indicate the rift phase that immediately preceded early Paleozoic post-rift cooling could not have occurred more than 10–20 Ma prior to 575 ± 25 Ma. These data, together with recently reported isotopic data that suggest deposition of the Windermere Supergroup began ~730–770 Ma, indicate that the rift-like deposits of the Windermere Supergroup are too old to represent the rifting that led directly to the deposition of the Cambro-Ordovician post-rift strata. Instead, Windermere sedimentation was apparently initiated by an earlier rift event, probably of regional extent, that was part of a protracted, episodic rift history that culminated with continental breakup in the latest Proterozoic – Early Cambrian.

Stratigraphy and deformational history of the Scrip Nappe, Monashee Mountains, British Columbia

1983 ◽  
Vol 20 (4) ◽  
pp. 639-650 ◽  
Author(s):  
Robert P. Raeside ◽  
Philip S. Simony
Keyword(s):  
British Columbia ◽  
Lower Limb ◽  
Rocky Mountains ◽  
Metamorphic Grade ◽  
Deformational History ◽  
Crenulation Cleavage ◽  
Deformation Phase ◽  
Nappe Complex ◽  
Selkirk Mountains ◽  
History Of

The Scrip Nappe, a large recumbent anticline that occupies the northern Selkirk and northern Monashee Mountains, has an inverted lower limb, some 50 km in length across strike, and comprises stratigraphic divisions of the Hadrynian Horsethief Creek Group, which can be traced southward with decreasing metamorphic grade through the Selkirk Mountains to the northern Purcell Mountains. The Scrip Nappe has a southwesterly vergence and it formed that way during the first folding phase of the Mesozoic Columbian Orogeny. Metamorphism no greater than biotite zone accompanied that first deformation. The nappe was subsequently refolded into tight northeast verging folds. Metamorphism rose to upper amphibolite facies late in the second deformation phase. After the metamorphic climax, northeast verging buckle folds and associated crenulation cleavage formed locally during a third folding episode. The entire nappe complex was then carried northeastward, on the Purcell thrust, over the folds and thrusts of the western Rocky Mountains.

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