Nina Creek Group and Lay Range Assemblage, north-central British Columbia: remnants of late Paleozoic oceanic and arc terranes

Ferri, Filippo

doi:10.1139/e17-070

Cited by 27 publications

(14 citation statements)

References 41 publications

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“…1) (Murphy et al in press). The Campbell Range Formation is correlative with the Slide Mountain assemblage of northern British Columbia (Nelson 1993;Ferri 1997). Our findings are consistent with the basalts of the TFZ being the along-strike continuation of the Campbell Range basalts.…”

Section: Discussionsupporting

confidence: 84%

“…The fault zone is underlain by Middle to Late Permian ocean-floor basalt and chert akin to that of the Slide Mountain terrane. The Slide Mountain terrane has been interpreted as oceanic crust formed in a marginal basin that likely had a width of hundreds to thousands of kilometres (see Ferri 1997, and references therein, for a discussion). An across-strike width of only 3-4 km of the Slide Mountain terrane appears to be preserved within the TFZ (Fig.…”

Section: Discussionmentioning

confidence: 99%

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Geology and juxtaposition history of the Yukon-Tanana, Slide Mountain, and Cassiar terranes in the Glenlyon area of central Yukon

Colpron

Gladwin²,

Johnston

et al. 2005

Can. J. Earth Sci.

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Abstract:In central Yukon, the pericratonic Yukon-Tanana terrane (YT) is juxtaposed with the Cassiar terrane (CT, parautochthonous North America) along the Tummel fault zone (TFZ), a 3-4 km wide, northwest-trending belt comprising imbricate fault slices of Slide Mountain terrane (SM, greenstone, chert, serpentinite) and synorogenic clastic rocks. Northeast of the TFZ, the CT comprises Paleozoic metapelitic rocks, marble, and amphibolite of continental margin affinity. To the southwest, the YT consists of a pre-Late Devonian metasedimentary complex overlain and intruded by Mississippian clastic, volcanic, and plutonic successions of continental arc affinity. In the TFZ, Middle to Late Permian ocean-floor basalt of the SM shows evidence of crustal contamination, suggesting deposition at the edge of a marginal ocean basin. Deformation features in the TFZ include early ductile fabrics overprinted by younger brittle structures. Triassic synorogenic clastic rocks in the TFZ, and at the base of a klippen above the YT, suggest that terrane imbrication began shortly after the Early Triassic.40 Ar/ 39 Ar mica ages from the region suggest cooling of the YT, SM, and part of CT below 300°C by Early Jurassic time. Pervasive brittle structures in the Ragged Lake klippe, which roots into the TFZ, indicate brittle thrusting of the SM over the CT in post-Triassic time. Early Cretaceous plutons intrude the CT (Glenlyon Batholith) and the TFZ (leucogabbro) and impose a contact aureole that extends westward into the YT. Steep brittle structures that deformed the TFZ also affect, in part, the Glenlyon Batholith but do not significantly offset its contact aureole. Consequently, little displacement can have occurred along the TFZ after Early Cretaceous time.Résumé : Dans le centre du Yukon, le terrane péricratonique Yukon-Tanana (YT) est juxtaposé au terrane Cassiar (CTAmérique du Nord parautochtone) le long de la zone de faille Tummel (TFZ) -une ceinture de 3 à 4 km de large, à tendance nord-ouest et comprenant des tranches de faille imbriquées du terrane de Slide Mountain (SM -roches vertes, chert, serpentinite) et des roches clastiques synorogéniques. Au nord-est de la TFZ, le CT comprend des roches métapélitiques, du marbre et des amphibolites d'affinité de bordure continentale datant du Paléozoïque. Vers le sud-ouest, le YT comprend un complexe métasédimentaire datant du pré-Dévonien tardif; des successions volcaniques et plutoniques, d'affinité d'arc continental, datant du Mississippien, le recouvrent et le pénètrent. Dans la TFZ, un basalte de plancher océanique (Permien moyen à tardif) du terrane de SM montre des évidences de contamination crustale suggérant une déposition à la bordure d'un bassin océanique. Les caractéristiques de déformation dans la TFZ comprennent une surimpression des textures ductiles précoces par des structures cassantes plus jeunes. Les roches clastiques synorogéniques (Trias) dans la TFZ et à la base d'une klippe au-dessus du YT, indiqueraient que l'imbrication des terranes a débuté peu de temps après l...

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Section: Discussionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Geology and juxtaposition history of the Yukon-Tanana, Slide Mountain, and Cassiar terranes in the Glenlyon area of central Yukon

Colpron

Gladwin²,

Johnston

et al. 2005

Can. J. Earth Sci.

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“…Elsewhere, the STG is in fault contact with the underlying Cache Creek Group, a marine volcanosedimentary sequence that is highly deformed and typically metamorphosed to the greenschist facies (Monger 1977). The QTG is stratigraphically underlain by the Permo-Pennsylvanian Lay Range Assemblage (Ferri 1997). This last assemblage comprises an internally imbricated fault slice, composed mainly of phyllite, chlorite schist, and metavolcanic rocks, that separates the QTG from Precambrian basement rocks (Nelson and Bellefontaine 1996).…”

Section: Geological Settingmentioning

confidence: 99%

Upper Triassic Takla Group volcanic rocks, Stikine Terrane, north-central British Columbia: geochemistry, petrogenesis, and tectonic implications

Dostál¹,

Gale²,

Church³

1999

Can. J. Earth Sci.

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The Upper Triassic Takla Group volcano-sedimentary assemblage is part of the Stikine Terrane of the Intermontane Belt in the Canadian Cordillera and covers an area of more than 30 000 km 2 in a belt up to 50 km wide and more than 800 km long. In the McConnell Creek area of north-central British Columbia, the assemblage consists of plagioclase-clinopyroxene-phyric, dominantly basaltic to andesitic flows and pyroclastic rocks, interlayered with volcanogenic sedimentary rocks. Compositionally, the volcanic rocks are intermediate between tholeiitic and calcalkaline. Their mantle-normalized trace element patterns are characterized by a moderate large-ion lithophile element enrichment and Nb and Ti depletion, suggesting that magmatism occurred in a volcanic-arc setting. Flat, heavy rare earth element chondrite-normalized patterns with (La/Yb) n ratios from 2 to 4.5 suggest that the parent magma was produced by mantle melting in the spinel stability field. The low Sr isotopic ratios ( 87 Sr/ 86 Sr i ≈ 0.7033-0.7043) and positive ε Nd values (-+7) indicate that an older sialic crust was not involved in their genesis. A coeval and compositionally similar volcano-sedimentary assemblage, also of the Takla Group, occurs in the adjacent Quesnel Terrane, in fault contact with the Stikinian Takla Group. Chemical resemblances between the Takla Groups of the Stikine and Quesnel terranes suggest that the volcanic assemblages may have had similar source compositions and melt histories. These results emphasize larger scale similarities between the Stikine and Quesnel terranes and suggest the Upper Triassic volcanic suites represent different fragments of the same early Mesozoic arc system.Résumé : L'assemblage volcano-sédimentaire du Groupe de Takla, du Trias supérieur, représente une partie du terrane de Stikine dans le Domaine intermontagneux de la Cordillère au Canada, il couvre une aire dépassant 30 000 km 2 et forme une ceinture d'une largeur maximum de 50 km et une longueur de plus de 800 km. Dans la région de McConnell Creek du nord-central de la Colombie-Britannique, l'assemblage est formé de plagioclase-clinopyroxènephyriques, avec prédominance de coulées de composition basaltique à andésitique et de roches pyroclastiques, interstratifiées avec des roches sédimentaires volcanogéniques. Les roches volcaniques ont une composition intermédiaire entre tholéiitique et calco-alcaline. Les diagrammes des éléments en traces normalisés au manteau sont caractérisés par un enrichissement modéré en éléments lithophiles à grand rayon ionique, et par un appauvrissement en Nd et Ti, suggérant que l'activité magmatique s'est manifestée dans un contexte d'arc volcanique. Les diagrammes à profil plat des terres rares lourdes normalisés aux chondrites, avec les rapports (La/Yb) n variant de 2 à 4,5 suggèrent que le magma parental fut produit par la fusion du manteau sous les conditions du champ de stabilité du spinelle. Les faibles rapports isotopiques ( 87 Sr/ 86 Sr i ≈ 0,7033-0,7043) et les valeurs positives de ε Nd (-+7) indiquent l'absenc...

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“…It is notable that during the Pennsylvanian to Early Permian there was extensive juvenile magmatism, both in Yukon-Tanana and in the coeval Slide Mountain backarc ocean, with juvenile isotopic signatures (i.e., εNd t >0) recorded in both the Yukon-Tanana terrane (Simard et al, 2003) and in the Slide Mountain terrane (Klepacki , 1985;Struik and Orchard, 1985;Nelson, 1993;Roback et al, 1994;Ferri, 1997;Lapierre et al, 2003; this study). Despite episodic rifting over a 100-million-year history within the Slide Mountain ocean starting in the Late Devonian, igneous rocks of Pennsylvanian to Early Permian age are disproportionately preserved, and those that are preserved have predominantly juvenile isotopic signatures.…”

Section: Implications For Crustal Growth At the Western North Americamentioning

confidence: 66%

Lithosphere-asthenosphere mixing in a transform-dominated late Paleozoic backarc basin: Implications for northern Cordilleran crustal growth and assembly

2012

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The Slide Mountain terrane is part of a North American Cordillera-long backarc basinal assemblage that developed between the ensialic arc terranes (Yukon-Tanana and affi liated pericratonic terranes) and the North American craton in the middle to late Paleozoic. The Slide Mountain basin started to open in the Late Devonian, and spreading continued through the late Paleozoic in an oblique (transform-dominated) manner such that the pericratonic terranes were translated into southerly latitudes. The basin closed, also in an oblique manner, by the Early Triassic, resulting in the reaccretion of the Yukon-Tanana terrane to the northwestern Laurentian margin. Both the opening and closing likely involved hundreds to possibly thousands of kilometers of intra-ocean and/or intra-arc strike-slip displacement, sinistral during the ocean's Late Devonian to mid-Permian opening and dextral during its Late Permian closing.In southeastern Yukon, Canada, the Early Permian Slide Mountain terrane is dominated by mafi c and ultramafi c volcanic and plutonic rocks of the Campbell Range Formation. These rocks are narrowly distributed, for over 300 km, on either side of the Jules Creek-Vangorda fault, a fault that separates Slide Mountain terrane from Yukon-Tanana terrane. The Campbell Range basaltic volcanic and high-level intrusive rocks have geochemical and isotopic signatures that vary systematically across the Jules Creek-Vangorda fault: ocean-island basalt (OIB) and enriched mid-ocean ridge basalt (E-MORB) suites with lower εNd t occur exclusively south of the fault, whereas north of the fault they have normal midocean ridge basalt (N-MORB) and backarc basin basalt (BABB) signatures with higher εNd t values. The εNd t values are inversely correlated with Nb/Th pm and Nb/La pm , suggesting that the lower εNd t values present in the E-MORB and OIB are mantle source features of these basalts and not due to continental crustal contamination. Isotopic and multi-element mixing calculations illustrate that the OIB-like basalts were derived primarily from enriched continental lithospheric mantle, whereas the N-MORB and BABB suites were sourced primarily from the upwelling backarc asthenospheric mantle; E-MORBs represent mixtures of depleted asthenospheric and enriched lithospheric mantle. The geochemical and isotopic variations in the Campbell Range Formation across the Jules Creek-Vangorda fault is attributed to formation in different parts of an extending continental-backarc basin and then their subsequent juxtaposition by continued displacement along the fault.Despite the juvenile isotopic signatures present in the Slide Mountain terrane, they occur as thin klippe atop rocks of recycled continental crustal affi nity, suggesting that they were likely only minor contributors to Cordilleran crustal growth.

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Nina Creek Group and Lay Range Assemblage, north-central British Columbia: remnants of late Paleozoic oceanic and arc terranes

Abstract: In north-central British Columbia, a belt of upper Paleozoic volcanic and sedimentary rocks lies between Mesozoic arc rocks of Quesnellia and Ancestral North America. These rocks belong to two distinct terranes: the Nina

Cited by 27 publications

References 41 publications

Geology and juxtaposition history of the Yukon-Tanana, Slide Mountain, and Cassiar terranes in the Glenlyon area of central Yukon

Geology and juxtaposition history of the Yukon-Tanana, Slide Mountain, and Cassiar terranes in the Glenlyon area of central Yukon

Upper Triassic Takla Group volcanic rocks, Stikine Terrane, north-central British Columbia: geochemistry, petrogenesis, and tectonic implications

Lithosphere-asthenosphere mixing in a transform-dominated late Paleozoic backarc basin: Implications for northern Cordilleran crustal growth and assembly

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