Upper Cambrian to Lower Silurian stratigraphic framework of platform-to-basin fades, northeastern British Columbia

Pyle, Leanne J.; Barnes, Christopher R.

doi:10.2113/48.2.123

Cited by 20 publications

(11 citation statements)

References 48 publications

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“…From central Yukon to northern British Columbia, Cambrian-Ordovician volcanism was coincident with shale deposition in relatively anoxic conditions ( Fig. 3; Cecile et al, 1982;Abbott et al, 1986;Cecile and Norford, 1991;MacIntyre, 1998;Pyle and Barnes, 2000;Pigage, 2009;, suggesting that at least some sedimentation occurred in deep-marine environments (e.g., Goodfellow et al, 1995;MacIntyre, 1998). Farther south in the Roberts Mountain allochthon of Nevada, Middle to Late Ordovician greenstone and faulting are associated with a chert-argillite basinal sequence (Madrid, 1987;Turner et al, 1989).…”

Section: Syn-to Post-breakup Volcanism Along the Cordilleran Marginmentioning

confidence: 99%

Early Paleozoic post-breakup magmatism along the Cordilleran margin of western North America: New zircon U-Pb age and whole-rock Nd- and Hf-isotope and lithogeochemical results from the Kechika group, Yukon, Canada

et al. 2019

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Post-breakup magmatic rocks are recognized features of modern and ancient passive margin successions around the globe, but their timing and significance to non-plume-related rift evolution is generally uncertain. Along the Cordilleran margin of western North America, several competing rift models have been proposed to explain the origins of post-breakup igneous rocks that crop out from Yukon to Nevada. New zircon U-Pb age and whole-rock geochemical studies were conducted on the lower Paleozoic Kechika group, south-central Yukon, to test these rift models and constrain the timing, mantle source, and tectonic setting of post-breakup magmatism in the Canadian Cordillera. The Kechika group contains vent-proximal facies and sediment-sill complexes within the Cassiar platform, a linear paleogeographic high that developed outboard of continental shelf and trough basins. Chemical abrasion (CA-TIMS) U-Pb dates indicate that Kechika group mafic rocks were generated during the late Cambrian (488–483 Ma) and Early Ordovician (473 Ma). Whole-rock trace-element and Nd- and Hf-isotope results are consistent with the low-degree partial melting of an enriched lithospheric mantle source during margin-scale extension. Equivalent continental shelf and trough rocks along western North America are spatially associated with transfer-transform zones and faults that were episodically reactivated during Cordilleran rift evolution. Post-breakup rocks emplaced along the magma-poor North Atlantic margins, including those near the Orphan Knoll and Galicia Bank continental ribbons, are proposed modern analogues for the Kechika group. This scenario calls for the release of in-plane tensile stresses and off-axis, post-breakup magmatism along the nascent plate boundary prior to the onset of seafloor spreading.

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Section: Syn-to Post-breakup Volcanism Along the Cordilleran Marginmentioning

confidence: 99%

Early Paleozoic post-breakup magmatism along the Cordilleran margin of western North America: New zircon U-Pb age and whole-rock Nd- and Hf-isotope and lithogeochemical results from the Kechika group, Yukon, Canada

et al. 2019

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“…The Atan Group, where originally described in the McDame map sheet (104P, Gabrielse 1954Gabrielse , 1963, disconformably overlies the Late Proterozoic Stelkuz Formation (Mansy and Gabrielse 1978;Fritz and Crimes 1985) and is disconformably overlain by the Late Cambrian Kechika Formation (Pyle and Barnes 2000). The type section of the Atan Group was divided into the Boya and Rosella formations (Fritz 1980b).…”

Section: Regional Geologymentioning

confidence: 99%

“…The turbidites were apparently deposited between northwest-trending, shallow-water carbonate buildups that developed on the tops of rotated rift-related horsts within the graben system (Fritz et al 1991;Ferri et al 1999). A change in the regional subsidence regime in the Middle Cambrian resulted in deposition of a platform to trough, carbonate to shale transition within the Kechika Formation (Pyle and Barnes 2000;Fig. 2), with basin expansion resulting in maximum development of the Kechika Trough in the Middle Devonian.…”

Section: Introductionmentioning

confidence: 99%

The Middle Cambrian Mount Roosevelt Formation (new) of northeastern British Columbia: evidence for rifting and development of the Kechika Graben System

Post

Long

2008

Can. J. Earth Sci.

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The eastern margin of the Kechika Graben in the vicinity of Muncho and Moose lakes, northeastern British Columbia, contains Middle Cambrian rift-related strata herein named the Mount Roosevelt Formation. The formation conformably overlies a quartzite package equivalent to the uppermost clastic unit of the informal late Early Cambrian Gataga group (Bonnia-Olenellus zone) and is conformably overlain by a thick, unnamed carbonate sequence of Middle Cambrian age (Plagiura-Poliella zone). The Mount Roosevelt Formation is subdivided into three members. The lowermost member is characterized by oöid-bearing siltstone and sandstone, interbedded with dolostone, limestone, and hematitic conglomerate. Conformably above this, the middle member is a thick sequence of polymict cobbly pebble conglomerate. The upper member includes karstified dolostone, calcareous-cemented conglomerate and sandstone, and limestone. Collectively the Mount Roosevelt Formation reflects alluvial fan delta progradation into a transgressive marine environment. Deposition occurred in an active fault-controlled basin, located on the eastern margin of the Kechika Graben adjacent to the Muskwa High. Basin initiation in the late Early Cambrian coincided with the reactivation of pre-existing regional faults. High rates of subsidence during the initial phase of extension were accommodated on these faults, which provided a locus for fan delta deposition. Continuing high rates of subsidence limited basinward fan delta development. Deposition of the formation ended with base-level transgression in the early Middle Cambrian that drowned the fan deltas and the adjacent Muskwa High and allowed development of the Kechika Trough above the older graben system. Résumé :Située à proximité des lacs Muncho et Moose dans le nord-est de la Colombie-Britannique, la bordure est du graben de Kechika contient des strates, ici nommées la Formation de Mount Roosevelt (Cambrien moyen), qui sont reliées à la distension. La formation repose en concordance sur un ensemble de quartzite équivalent à l'unité supérieure, clastique, du groupe de Gataga, informel, datant du Cambrien précoce (zone à Bonnia-Olenellus); elle est recouverte en concordance par une épaisse séquence de carbonate, sans nom, datant du Cambrien moyen (zone à Plagiura-Poliella). La Formation de Mount Roosevelt est subdivisée en trois membres. Le membre inférieur est caractérisé par des siltstones et des grès à oolites, interstratifiés avec des dolomies, des calcaires, et des conglomérats hématitiques. Par-dessus, en concordance, le membre du centre est composé d'une épaisse séquence de conglomérat grenu, hétérogène et caillouteux. Le membre supérieur comprend de la dolomie karstifiée, du conglomérat et du grès à ciment calcaire, et du calcaire. Dans son ensemble, la Formation de Mount Roosevelt est le reflet de la progradation d'un delta alluvionnaire en un environnement marin de transgression. La déposition a eu lieu dans un bassin contrôlé par des failles actives situé sur la bordure est du graben de Kechika, voisi...

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“…No information on the Cambrian stratigraphy exists near the Pink Mountain Anticline; therefore the stratigraphy will be termed Cambrian undivided on the deeper seismic sections. The contact between the Cambrian units and the Ordovician Kechika Group has been described as a regional angular unconformity (Pyle and Barnes 2000, Glass 1997, Cecile and Norford 1979, Pugh 1975). shelf transition zone Norford 1979, Thompson 1989…”

Section: Cambrian (Lower To Upper Cambrian)mentioning

confidence: 99%

“…The Skoki Formation consists mostly of dolostone and minor limestones Barnes 2000, Thompson 1989) in which various authors have subdivided these units, but for the purposes of this study, the Skoki Formation will be traced on the seismic sections as one unit Barnes 2000, Cecile andNorford 1979). The Skoki Formation ranges in thickness from 62 metres in the southern Alberta Foothills to 1260 metres in the western half of the Halfway River Map area (Pyle and Barnes 2000, Glass 1997, Thompson 1989. Near the Ospika River (Figure 2-3…”

Section: Skoki Formation (Arenigian -Darrwilian)mentioning

confidence: 99%

Stratigraphy, structure and tectonic history of the Pink Mountain Anticline, Trutch (94G) and Halfway River (94B) map areas, northeastern British Columbia

Hinds¹,

Spratt

2005

Bulletin of Canadian Petroleum Geology

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Upper Cambrian to Lower Silurian stratigraphic framework of platform-to-basin fades, northeastern British Columbia

Cited by 20 publications

References 48 publications

Early Paleozoic post-breakup magmatism along the Cordilleran margin of western North America: New zircon U-Pb age and whole-rock Nd- and Hf-isotope and lithogeochemical results from the Kechika group, Yukon, Canada

Early Paleozoic post-breakup magmatism along the Cordilleran margin of western North America: New zircon U-Pb age and whole-rock Nd- and Hf-isotope and lithogeochemical results from the Kechika group, Yukon, Canada

The Middle Cambrian Mount Roosevelt Formation (new) of northeastern British Columbia: evidence for rifting and development of the Kechika Graben System

Stratigraphy, structure and tectonic history of the Pink Mountain Anticline, Trutch (94G) and Halfway River (94B) map areas, northeastern British Columbia

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