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>Evolution of the Coast Cascade Orogen by Tectonic Thickening and Magmatic Loading: The Cretaceous Breakenridge Complex, Southwestern British Columbia
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Evolution of the Coast Cascade Orogen by Tectonic Thickening and Magmatic Loading: The Cretaceous Breakenridge Complex, Southwestern British Columbia
A model for the tectono-magmatic mid-Cretaceous (110-80 Ma) evolution of the southern Coast belt is proposed. The first magma pulse represented by the 107-100 Ma Breakenridge pluton intruded within a magmatic arc as a set of shallow sills. It was initially buried by orogen-parallel contraction, followed by the emplacement of the 96-94 Ma Snowshoe pluton, which belongs to the second magma pulse. The Snowshoe pluton was emplaced by similar mechanisms in structurally higher levels of the crust. Orogen-normal compression was the final mechanism for deep burial and attainment of peak metamorphic conditions (500-680°C at 6.5-10.3 kbar) of the study area between 91-86 Ma. Following orogen-normal contraction and regional folding, oblique right-lateral strike-slip shearing occurred while rocks were in a ductile environment. The third magma pulse (86-84 Ma) was synchronous with the late stages of high-grade metamorphism and early stages of oblique strike-slip movement.
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机译：提出了南部海岸带构造-岩浆中白垩纪（110-80 Ma）演化的模型。以107-100 Ma Breakenridge岩体为代表的第一个岩浆脉冲侵入岩浆弧内，成为一组浅基岩。它最初是通过造山带平行收缩被掩埋的，然后是属于第二岩浆脉冲的96-94 Ma Snowshoe岩体。 Snowshoe岩体通过类似的机制放置在结构较高的地壳中。造山带正常压缩是深埋和达到91-86 Ma之间研究区域的最高变质条件（在6.5-10.3 kbar时为500-680°C）的最终机制。在造山带正常收缩和区域性折叠之后，岩石处于延性环境中时，发生了右斜走滑剪切作用。第三岩浆脉冲（86-84 Ma）与高级变质作用的晚期和斜走滑运动的早期同步。
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