| Popis: |
The Late Cretaceous Surprise Lake batholith in the Atlin district of northern British Columbia is a highly differentiated, fluoritic, and peraluminous subalkaline body of adamellite-granite composition. The presence of miarolitic cavities and chilled, fine-grained margins suggests it was emplaced at a high structural level, and its trace element signature indicates it has some within-plate granitoid characteristics. The batholith shows many chemical similarities to the I-type igneous rocks associated with W skarns in British Columbia, although it averages >2,700 ppm F, whereas plutons related to W skarns average |
