Age, construction, and exhumation of mid-crust of the Jurassic Bonanza arc, Vancouver Island, Canada
D. Canil et al., University of Victoria, School of Earth and Ocean Sciences, 3800 Finnerty Road, Victoria, British Columbia V8W 3P6, Canada http://dx.doi.org/10.1130/L225.1.
Dante Canil and colleagues present new U-Pb zircon ages for heterogeneous mafic-felsic rocks of the West Coast complex, a midcrustal plutonic component of exposed Jurassic arc-crustal section on Vancouver Island. They examine the timing of juvenile plutonic crust production and consanguinity of volcanism and plutonism in this arc. The midcrustal plutons were emplaced between 174 and 193 million years ago, contemporaneous with the upper-crustal (less than 10 km deep) plutonic component of the arc (Island plutonic suite). A 12-km thickness of plutonic arc crust was built as a series of sheets at a rate of about 0.003 cubic kilometers per year. Deformation and emplacement were contemporaneous, and there are no correlations among age, differentiation (peridotite to granite), or structural level of plutons in the arc. The age range and a weak eastward younging age polarity of th
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