The Cheslatta Lake suite: Miocene mafic, alkaline magmatism in central British Columbia

Anderson, Robert; Resnick, Jonah; Russell, James K.; Woodsworth, G.J.; Villeneuve, M.; Grainger, Nancy C.

doi:10.1139/cjes-38-4-697

Cited by 6 publications

(10 citation statements)

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“…Regional data (n = 223) collected from the following sources: Northern Cordilleran Volcanic Province (NCVP): Mt. Skukum [ Morris and Creaser , 2003], Bennett Lake [ Morris and Creaser , 2003], Alligator Lake [ Eiché et al , 1987], Hirschfield–Llangorse [ Francis and Ludden , 1995], Sloko Lake [ Resnick , 2003], Rancheria Volcanic Field [ Hasik , 1994], and Iskut River area [ Cousens and Bevier , 1995; Russell and Hauskdóttir , 2001]; Challis‐Kamloops Volcanic Belt (CKVB): Buck Creek Basin [ Dostal et al , 1998; Dostal et al , 2001], Cheslatta Lake and Chilcotin basalts [ Anderson et al , 2001], Masset Formation [ Hamilton and Dostal , 2001]; Anahim Volcanic Belt (AVB), Itcha Volcanic Complex [ Charland , 1994]. Coast Mountains plutonic rocks [ Girardi et al , 2008] with Ba/Th > 700 have been omitted from the shaded field, but all plutonic rocks have Nb/La < 1.…”

Section: Discussionmentioning

confidence: 99%

“…Numerous occurrences of mantle xenoliths exposed in the mafic rocks of western Canada have been observed [ Cousens and Bevier , 1995; Anderson et al , 2001; Harder and Russell , 2007] and described chemically [e.g., Francis , 1987; Carignan et al , 1996; Shi et al , 1998; Russell and Hauskdóttir , 2001; Peslier et al , 2000, 2002; Harder and Russell , 2006]. Xenoliths are dominantly spinel lherzolite in composition [ Francis , 1987; Carignan et al , 1996; Peslier et al , 2000], with subordinate occurrences of spinel harzburgite [ Francis , 1987; Peslier et al , 2000; Harder and Russell , 2006] and rare dunite [ Peslier et al , 2000].…”

Section: Discussionmentioning

confidence: 99%

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Isotopic and geochemical evidence for a recent transition in mantle chemistry beneath the western Canadian Cordillera

Manthei¹,

Ducea²,

Girardi³

et al. 2010

J. Geophys. Res.

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[1] New petrologic, geochemical, and isotopic data are reported from a suite of mafic dike and lava flow samples collected from sites within the western Canadian Cordillera. Samples range in age from Eocene to Quaternary and document a significant transition in mantle chemistry that occurred sometime after 10 Ma. Eocene to late Miocene basalts emplaced as dikes within the Coast Mountains Batholith contain abundant hornblende, are enriched in large ion lithophile elements (LILE) (Ba, Rb, K), have negative high field strength element (HFSE) (Nb, Ta) anomalies, and were likely derived from lithospheric mantle ( 87 Sr/ 86 Sr = 0.70353-0.70486; e Nd = +2.5 to +5.7) that was stabilized after the cessation of arc magmatism in the area. By contrast, Quaternary lava flows have lower LILE concentrations, positive Nb-Ta anomalies, and were likely generated by upwelling asthenosphere ( 87 Sr/ 86 Sr = 0.70266-0.70386; e Nd = +7.4 to +8.8) or at least a mantle source with different chemical and isotopic characteristics. A regional comparison of mafic rocks from western Canada that are also Eocene to Quaternary in age indicates that the transition in mantle chemistry after 10 Ma was pervasive and widespread and was not limited to the present study area. This transition occurred $40 Ma after the cessation of Cordilleran arc magmatism in central British Columbia, suggesting that large-scale transitions in mantle chemistry beneath magmatic arcs may occur on the order of tens of millions of years after the final subduction of oceanic lithosphere, in this case as a result of lithospheric thinning by continental extension.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Isotopic and geochemical evidence for a recent transition in mantle chemistry beneath the western Canadian Cordillera

Manthei¹,

Ducea²,

Girardi³

et al. 2010

J. Geophys. Res.

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“…East and north of the Pemberton arc, new voluminous mafi c and alkalic magmatism of nonsubduction character was activated. This new inboard activity included the northern Cordilleran volcanic province (Edwards and Russell, 1999) and the Cheslatta Lake suite portion of the Chilcotin basalts (Anderson et al, 2001). The Cheslatta Lake suite comprises a mafi c igneous suite of alkaline to transitional basalt and began erupting in mid-Miocene time, ca.…”

Section: -15 Mamentioning

confidence: 99%

“…21 Ma. Cheslatta magmatism is dominantly alkalic, and some fl ows demonstrate near primitive-mantle melt compositions and/or ultramafi c mantle-derived xenoliths (Anderson et al, 2001). These magmas have been interpreted as melts of an oceanisland-type mantle source.…”

Section: -15 Mamentioning

confidence: 99%

Cenozoic to Recent plate configurations in the Pacific Basin: Ridge subduction and slab window magmatism in western North America

et al. 2006

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“…It is filled with a thick Jurassic to Tertiary clastic succession, which was probably partly contiguous with, or at least contemporaneous with, Bowser successions. Neogene-Paleogene plateau basalts and intrusions form a widespread Tertiary succession covering 25,000 km 2 between 49°N and 55°N, which obscures the underlying successions and structures (Souther and Yorath 1991;Anderson et al 2001). Relative isolation and little subsurface geological information hinders the analysis of earlier Nechako history compared to regions where the younger volcanic successions are either eroded or absent.…”

Section: Regional Geological Settingmentioning

confidence: 99%

Cordilleran Intermontane thermotectonic history and implications for neotectonic structure and petroleum systems, British Columbia, Canada

Majorowicz

Osadetz

2007

Int J Earth Sci (Geol Rundsch)

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Heat flow increases northward along Intermontane Belt in the western Canadian Cordillera, as shown by geothermal differences between Bowser and Nechako sedimentary basins, where geothermal gradients and heat flows are~30 mK/m and~90 mW/m 2 compared tõ 32 mK/m and 70 -80 mW/m 2 , respectively. Sparse temperature profile data from these two sedimenatary basins are consistent with an isostatic model of elevation and crustal parameters, which indicate that Bowser basin heat flow should be~20 mW/m 2 greater than Nechako basin heat flow. Paleothermometric indicators record a significant northward increasing Eocene or older erosional denudation, up to~7 km. None of the heat generation, tectonic reorganization at the plate margin, or erosional denudation produce thermal effects of the type or magnitude that explain the north-south heat flow differences between Nechako and Bowser basins. The more southerly Nechako basin, where heat flow is lower, has lower mean elevation, is less deeply eroded, and lies opposite the active plate margin. In contrast, Bowser basin, where heat flow is higher, has higher mean elevation, is more deeply eroded, and sits opposite a transform margin that succeeded the active margin~40 Ma. Differences between Bowser and Nechako basins contrast with the tectonic history and erosion impacts on thermal state. Tectonic history and eroded sedimentary thickness suggest that Bowser basin lithosphere is cooling and contracting relative to Nechako basin lithosphere. This effect has reduced Bowser basin heat flow by~10-20 mW/m 2 since~40 Ma. Neither can heat generation differences explain the northerly increasing Intermontane Belt heat flow. A lack of extensional structures in the Bowser basin precludes basin and range-like extension. Therefore, another, yet an unspecified mechanism perhaps associated with the Northern Cordilleran Volcanic Province, contributes additional heat. Bowser basin's paleogeothermal gradients were higher,~36 mK/m, before the Eocene and this might affect petroleum and metallogenic systems.

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The Cheslatta Lake suite: Miocene mafic, alkaline magmatism in central British Columbia

Cited by 6 publications

References 0 publications

Isotopic and geochemical evidence for a recent transition in mantle chemistry beneath the western Canadian Cordillera

Isotopic and geochemical evidence for a recent transition in mantle chemistry beneath the western Canadian Cordillera

Cenozoic to Recent plate configurations in the Pacific Basin: Ridge subduction and slab window magmatism in western North America

Cordilleran Intermontane thermotectonic history and implications for neotectonic structure and petroleum systems, British Columbia, Canada

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