Upper Jurassic‐Lower Cretaceous basinal strata along the Cordilleran Margin: Implications for the accretionary history of the Alexander‐Wrangellia‐Peninsular Terrane

McClelland, William C.; Gehrels, George E.; Saleeby, Jason B.

doi:10.1029/92tc00241

Cited by 158 publications

(157 citation statements)

References 112 publications

Supporting

Mentioning

152

Contrasting

Order By: Relevance

“…Late Jurassic and Early Cretaceous GravinaNutzotin deposits along the west flank of the Coast Mountains north of latitude 55° and in the TyaughtonMethow basin in their east side south of latitude 52° were thought to have accumulated in post-accretionary, backarc and/or dextral pull-apart basins (Figs. 1, 2, 3;Gehrels and Saleeby 1987;McClelland et al 1992;van der Heyden 1992). However, these models did not take into account the fact that the Jurassic-Cretaceous TyaughtonMethow basin in the southeastern Coast Mountains is floored by remnants of oceanic lithosphere, some of which, in the Bridge River terrane, are as young as latest Middle Jurassic (164 Ma) and possibly even younger.…”

Section: Discussionmentioning

confidence: 99%

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

Monger

2014

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionmentioning

confidence: 99%

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

Monger

2014

View full text Add to dashboard Cite

show abstract

“…This composite terrane may have been accreted to the western margin of North America during mid-Cretaceous time, resulting in the widespread metamorphic and magmatic events of this age observed throughout coastal British Columbia and southeast Alaska (Monger et al, 1982;Crawford et al, 1987). McClelland and Gehrels (1990), McClelland et al (1992), and van der Heyden (1992) suggested that mid-Cretaceous colli- on November 29, 2014 lithosphere.gsapubs.org Downloaded from www.gsapubs.org | Volume 6 | Number 3 | LITHOSPHERE sional accretion was preceded by initial juxtaposition during mid-Jurassic time, followed by extension to form the Late Jurassic-Early Cretaceous Gravina basin (Fig. 1).…”

Section: U-pb and Hf Isotope Analysis Of Detrital Zircons From The Bamentioning

confidence: 99%

U-Pb and Hf isotope analysis of detrital zircons from the Banks Island assemblage (coastal British Columbia) and southern Alexander terrane (southeast Alaska)

et al. 2014

Self Cite

View full text Add to dashboard Cite

“…At that time, the Coast Belt formed as a tectonic welt resulting from the widespread plutonism, metamorphism and crustal shortening. However, other models argue that the superterranes were together by mid-Jurassic and the collisional orogen originated from intra-arc rifting and subsequent shortening (VAN DER HEYDEN, 1992;MCLELLAND et al, 1992). A partial resolution in the apparent conflict between these types of models has also been proposed (MONGER et al, 1994), involving left-lateral displacements before the mid-Cretaceous.…”

Section: Tectonic Settingmentioning

confidence: 99%

Upper Crustal Velocity Structure of the Southwestern Canadian Cordillera from Explosion Recordings on the WCTN Earthquake Seismic Net

Fallows

Spence

Rogers

2000

Pure appl. geophys.

View full text Add to dashboard Cite

The digital seismic network used to monitor earthquakes in southwestern British Columbia recorded explosions from Lithoprobe's Southern Cordillera Refraction Experiment (SCoRE) in 1989 and 1990 and from the USGS Pacific Northwest Refraction Survey in 1991. Both P and S waves were recorded. The geographical distribution of the shots and receiver stations enabled a large three-dimensional area to be sampled. For ray paths considered to be in the top 10 km of the crust, we used a tomographic inversion procedure to estimate the 2-D distribution of upper crustal P-and S-wave velocities within blocks of a refracting velocity grid, located beneath a near surface velocity layer of uniform thickness. The P-wave velocity distribution mapped the subsurface location of several terranes in the southwest Cordillera. Volcanic rocks of Wrangellia terrane, which is the principal component of the Insular Belt, were characterized by upper crustal velocities \ 6.3 km s − 1 , whereas plutonic rocks of the Coast Belt had velocities B 6.3 km s − 1 . East of southern Vancouver Island, the velocity distribution indicated that Wrangellia extends in the subsurface beneath the Coast Belt for about 130 km eastward of the surface location of the Insular/Coast Belt boundary. A portion of the southern boundary of Wrangellia was also delineated by the P-velocity map, which suggested that metamorphic rocks of the Northwest Cascades Thrust System may extend beneath sedimentary cover as far west as south-central Georgia Strait. Inverted S-wave velocities were typically 3.6 -3.7 km s − 1 . Corresponding values of Poisson's ratio were 0.27-0.28 over Vancouver Island and 0.20 -0.24 in the Coast Belt. The higher values for Vancouver Island likely reflect the high mafic content of Wrangellia volcanics, compared to the high quartz content of the Coast Belt plutonics.

show abstract

Upper Jurassic‐Lower Cretaceous basinal strata along the Cordilleran Margin: Implications for the accretionary history of the Alexander‐Wrangellia‐Peninsular Terrane

Abstract: Abstract. Upper Jurassic and Lower

Cited by 158 publications

References 112 publications

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

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

U-Pb and Hf isotope analysis of detrital zircons from the Banks Island assemblage (coastal British Columbia) and southern Alexander terrane (southeast Alaska)

Upper Crustal Velocity Structure of the Southwestern Canadian Cordillera from Explosion Recordings on the WCTN Earthquake Seismic Net

Contact Info

Product

Resources

About