Post–10 Ma uplift and exhumation of the northern Coast Mountains, British Columbia

Farley, K. A.; Rusmore, Margaret E.; Bogue, Scott W.

doi:10.1130/0091-7613(2001)029<0099:pmuaeo>2.0.co;2

Cited by 106 publications

(73 citation statements)

References 12 publications

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“…North of ~lati-tude 55°, the Coast Mountains are about 50-100 km wide but south of this are up to twice the width. The rugged mountainous topography results from differential uplift of up to 4 km in the last 10 million years with increased rates of exhumation in the last 4 million years, together with glacial and fluvial sculpting of hard bedrock in a region of high precipitation (Parrish 1983;Farley et al 2001 (Fig. 2).…”

Section: Coast Mountains: Core Of the Coast-cascade Orogen (Cco)mentioning

confidence: 99%

Logan Medallist 1. Seeking the Suture: The Coast-Cascade Conundrum

Monger

2014

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The boundary between rocks assigned to the Intermontane superterrane in the interior of the Canadian Cordillera and those of the Insular superterrane in the westernmost Cordillera of British Columbia and southeastern Alaska lies within/along the Coast Mountains, in which is exposed the core of an orogen that emerged as a discrete tectonic entity between 105 and 45 million years ago. Evidence from the Coast Mountains and flanking areas indicates that parts of the Intermontane superterrane (in Stikinia and Yukon-Tanana terranes) were near those of the Insular superterrane (Wrangellia and Alexander terranes) by the Early Jurassic (~180 Ma). This timing, as well as paleobiogeographic and paleomagnetic considerations, appears to discount a recent hypothesis that proposes westward-dipping subduction beneath an intra-oceanic arc on Insular superterrane resulted in arc-continent collision and inaugurated Cordilleran orogenesis in the Late Jurassic (~146 Ma). The hypothesis also relates the subducted ocean that had separated the superterranes to a massive, faster-than-average-velocity seismic anomaly in the lower mantle below the eastern seaboard of North America. To create such an anomaly, subduction of the floor of a large ocean was needed. The only surface record of such an ocean in the interior of the Canadian Cordillera is the Cache Creek terrane, which lies within the Intermontane superterrane but is no younger than Middle Jurassic (~174 Ma). This terrane, together with the probably related Bridge River terrane in the southeastern Coast Mountains, which is as young as latest Middle Jurassic (164 Ma) and possibly as young as earliest Cretaceous (≥ 130 Ma), appear to be the only candidates in Canada for the possible surface record of the seismic anomaly. SOMMAIRELa limite entre les roches assignées au Superterrane d’intermont de l’intérieur des Cordillères canadiennes et celles du Superterrane insulaire dans la portion la plus à l’ouest de la Cordillère de Colombie-Britannique et du sud-est de l’Alaska se trouvent dans et au long de la Chaîne côtière, au sein de laquelle affleure le noyau d’un orogène qui est apparu comme entité tectonique distincte entre 105 et 45 millions d’années. Des indices de la Chaîne côtière et des régions environnantes montrent que des portions du Superterrane d’intermont (dans les terranes de Stikinia et de Yukon-Tanana) se trouvaient alors près de celles du Superterrane insulaire (terranes de Wrangellia et d’Alexander) au début du Jurassique (~180 Ma). Cette chronologie, ajoutée à certains facteurs paléobiogéographiques et paléomagnétiques semblent discréditer une hypothèse récente voulant qu’une subduction à pendage ouest sous un arc intra-océanique sur le Superterrane insulaire résultait d’une collision entre un arc et le continent, initiant ainsi l’orogénèse de la Cordillère à la fin du Jurassique (~146 Ma). Cette hypothèse relie aussi l’océan subduit qui séparait les superterranes à une anomalie de vitesse sismique plus rapide que la normale dans le manteau inférieur sous le littoral maritime oriental de l’Amérique du Nord. Pour créer une telle anomalie, la subduction du plancher d’un grand océan était nécessaire. La seule indication de surface de l’existence d’un tel océan à l’intérieur de la Cordillère canadienne est le terrane de Cache Creek qui, bien qu’il se trouve dans le Superterrane d’intermont, est plus ancien que le Jurassique moyen (~174 Ma). Ce terrane, avec son équivalent probable de Bridge River dans le sud-est de la Chaîne côtière, qui est aussi jeune que la fin du Jurassique (164 Ma) et peut-être aussi jeune que le début du Crétacé (≥ 130 Ma), semblent être les seuls candidats au Canada offrant des vestiges en surface de cette anomalie sismique.

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Section: Coast Mountains: Core Of the Coast-cascade Orogen (Cco)mentioning

confidence: 99%

Logan Medallist 1. Seeking the Suture: The Coast-Cascade Conundrum

Monger

2014

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“…2). These studies constitute a regional scale database that indicates a significant acceleration of rock exhumation rates during the Late Miocene (Reiners et al, 2002;Parrish, 1983;O'Sullivan and Parrish, 1995;Fitzgerald et al, 1995;O'Sullivan and Currie, 1996;Farley et al, 2001). On its own such information should be interpreted in terms of surface uplift with caution.…”

Section: Topographic Evolution Of the North American Cordilleramentioning

confidence: 99%

Mountain uplift and the glaciation of North America – a sensitivity study

2010

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Abstract. The Miocene (∼24 to ∼5 million years ago) was a period of relative global warmth compared to the Quaternary (∼2 million years ago to present; e.g. Zachos et al., 2001) and was characterised by the intermittent glaciation of Antarctica only. Paradoxically, the majority of available proxy data suggest that during the Miocene, pCO 2 was similar, or even lower, than the pre-industrial levels (280 ppmv; Pagani et al

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“…The average grain-radius of the samples analyzed is 61 microns, corresponding to a closure temperature of 75 ºC, assuming a linear cooling rate of 10 ºC/my (1). Errors reported for the helium ages reflect the 2 sigma standard error of all of the samples in this study (9). Additional analytical details and results are shown in Tables S1-S3 (helium) and Tables S4, S5, S6 and S7 (apatite fission track).…”

mentioning

confidence: 99%

Uplift in the Fiordland Region, New Zealand: Implications for Incipient Subduction

Gurnis

Kamp

Sutherland³

2002

Science

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Provided that exhumation related to subduction initiation removes at least 2-3 km of material, then it may be detected using low temperature thermochronometry. Such techniques yield cooling ages which can be interpreted to reflect the approximate time that a particular rock has passed through the closure temperature of the particular mineral system. Here we rely on helium and fission track ages in apatite. The closure temperature of helium in apatite is roughly 70 ºC (1) We obtained age apatite helium and fission track age pairs for samples from vertical elevation profiles adjacent to central Doubtful Sound and Lake Hauroko, and at Percy Saddle, as well as two transects at sea level along Dusky and Doubtful Sounds, and one lake-level transect along the North Fiord of Lake Te Anau. In addition to these

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Post–10 Ma uplift and exhumation of the northern Coast Mountains, British Columbia

Cited by 106 publications

References 12 publications

Logan Medallist 1. Seeking the Suture: The Coast-Cascade Conundrum

Logan Medallist 1. Seeking the Suture: The Coast-Cascade Conundrum

Mountain uplift and the glaciation of North America – a sensitivity study

Uplift in the Fiordland Region, New Zealand: Implications for Incipient Subduction

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