Eocene tectonics in the Omineca Belt, northern British Columbia, Canada: Field, 40Ar-39Ar, and fission track data from the Horseranch Range

Plint, H. E.; Erdmer, Philippe; Reynolds, P. H.; Grist, A. M.

doi:10.1130/0016-7606(1992)104<0106:etitob>2.3.co;2

Cited by 7 publications

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“…This increase in obliquity would result in relaxation of orogen perpendicular shortening that would lead to crustal extension in an overall dextral transtensional regime [e.g., Struik , 1992; Ewing , 1980]. The occurrences of the highest‐grade metamorphic rocks in British Columbia in the footwalls of major Eocene extensional systems such as the Shuswap Complex and Monashee Complex [ Parrish et al , 1988], the Wolverine Complex and Horseranch Range [ Struik , 1992; Plint et al , 1992], the Tatla Lake Complex [ Friedman and Armstrong , 1988] and the Coast Plutonic Complex between 54° and 55°N (this study) suggests that hot partially molten crust localized extensional strain during dextral transtension of the Cordilleran lithosphere.…”

Section: Discussionmentioning

confidence: 99%

Strain partitioning in an obliquely convergent orogen, plutonism, and synorogenic collapse: Coast Mountains Batholith, British Columbia, Canada

Andronicos¹,

Chardon²,

Hollister

et al. 2003

Tectonics

104

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We describe the crustal structure of the Coast Mountains batholith between 54° and 55°N, within the Canadian Cordillera, with emphasis on emplacement of the 7 km thick Kasiks sill complex (KSC). Kinematic patterns that developed during emplacement of the KSC are the result of interactions between magma transport, magma accumulation and regional deformation. The sills were emplaced during NW directed normal shearing and flattening of country rocks that host the KSC. A ∼2 km thick shallowly NE dipping mylonite zone cuts the eastern side of the KSC. Kinematic indicators within the mylonite zone record top to the east normal displacements. Structural analysis shows that mylonite formation occurred during subvertical shortening and east‐northeast, subhorizontal extension. U/Pb zircon age dates show that ENE directed normal shearing along the eastern side of the KSC and WNW directed normal shearing within the KSC occurred contemporaneously between ∼54 and 51 Ma, indicating strong strain partitioning between the mylonite and the KSC. This pattern of strain partitioning is interpreted to have been driven by return flow of melt‐laden crust in response to tectonic denudation of the upper crust. Seismic profiling shows that many of these structures extend to mid and lower crustal depths. Comparison of our results with other regions within the Canadian Cordillera indicates that orogen‐scale right‐lateral strike‐slip faults deformed synchronously with wide spread magmatism and formation of extensional gneiss domes. Thus the crustal structure of the Coast Mountains batholith was the result of early Tertiary batholith construction during dextral oblique convergence and synorogenic collapse.

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Section: Discussionmentioning

confidence: 99%

Strain partitioning in an obliquely convergent orogen, plutonism, and synorogenic collapse: Coast Mountains Batholith, British Columbia, Canada

Andronicos¹,

Chardon²,

Hollister

et al. 2003

Tectonics

104

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“…In the text this is called the OkanaganShuswap Complex. Horseranch Complex from Plint et al (1992), Sifton Complex from Evenchick (1985), Tatla Lake Complex from Friedman and Armstrong (1988), Wolverine Complex from Struik (1990), Ferri and Melville (1988), and Wheeler and McFeely (1987), and the Shuswap Complex from Wheeler and McFeely (1987). MR. Mesilinka River.…”

Section: Introductionmentioning

confidence: 98%

Intersecting intracontinental Tertiary transform fault systems in the North American Cordillera

Struik¹

1993

Can. J. Earth Sci.

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In central British Columbia, north-trending dextral strike-slip faults that cut Late Eocene granite also truncate northwesttrending dextral strike-slip faults. The northwest-trending strike-slip faults bound the Wolverine Metamorphic Complex (Wolverine Complex), which has been uplifted primarily by northwest-southeast Eocene crustal extension and somewhat by Late Eocene northerly extension. The crustal extension is indicated by shallow-dipping extensions faults, dyke complexes, and stretching lineations. The Wolverine Complex and its bounding faults define a crustal pull-apart in an en echelon dextral transform. The northwest-and north-trending dextral strike-slip faults in central British Columbia are the continuations of faults that transect the interior of the North American Cordillera, and they represent at least two distinct plate boundaries intermittently active during the Early to Middle Eocene, and the Late Eocene to Early Oligocene. Each of these systems consists of en echelon strike-slip faults linked by extensional pull-aparts, locally represented by metamorphic core complexes. These two plate-boundary systems represent two distinct plate-motion configurations between the North American and Kula-Pacific plates. The older plate boundary is truncated and disrupted by the younger one. These two systems may in turn be disrupted by a younger and different plate-motion configuration represented by the transverse Basin and Range extension complex and its northern and southern transform boundary faults.Les failles coulissantes dextres, de direction nord, dans le centre de la Colombie-Britannique, qui coupent les massifs de granite d'bge Cockne tardif, tronquent aussi les failles coulissantes dextres qui sont orientkes nord-ouest. Les failles coulissantes de direction nord-ouest encadrent le Complexe mktamorphique de Wolverine (Complexe de Wolverine), principalement souleve A 1'Eocbne par une extension crustale nord-ouest -sud-est, et partiellement A 1'Eocbne tardif par une extension vers le nord. Les failles de dktachement, les complexes filoniens et les lineations d'ktirement sont les tCmoins de I'extension crustale. Le Complexe de Wolverine et ses failles bordikres definissent un bassin transtension crustal, dCveloppC dans une faille transformante dextre en tchelons. Dans le centre de la Colombie-Britannique, les failles coulissantes dextres de direction nord-ouest et nord representent le prolongement des failles qui transectent I'intCrieur de la Cordillbre de 1'AmCrigue du Nord, et elles indique~t au moins deux bordures distinctes de plaques qui furent Lpisodiquement actives durant 1'Eockne moyen i precoce, et 1'Eockne tardif i I'Oligockne precoce. Chacun de ces systkmes comprend de failles coulissantes en CcheIons relites par des bassins de transtension extensifs, et localement ils correspondent h des noyaux de massifs mktamorphiques. Ces deux systbmes de bordures de plaques reprtsentent deux modes distincts de mouvements entre les plaques de 1'AmCrique du Nord et de Kula -Pacifique. La plus ancienne des b...

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Response of continental magmatic arcs to regional tectonic changes recorded by synorogenic plutons in the middle crust: An example from the Coast Mountains of British Columbia

Depine

Andronicos

Hollister

2011

Journal of Structural Geology

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Eocene tectonics in the Omineca Belt, northern British Columbia, Canada: Field, 40Ar-39Ar, and fission track data from the Horseranch Range

Cited by 7 publications

References 0 publications

Strain partitioning in an obliquely convergent orogen, plutonism, and synorogenic collapse: Coast Mountains Batholith, British Columbia, Canada

Strain partitioning in an obliquely convergent orogen, plutonism, and synorogenic collapse: Coast Mountains Batholith, British Columbia, Canada

Intersecting intracontinental Tertiary transform fault systems in the North American Cordillera

Response of continental magmatic arcs to regional tectonic changes recorded by synorogenic plutons in the middle crust: An example from the Coast Mountains of British Columbia

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