northwest of shir-kuh batholith, a number of leucocratic granitic and granodioritic plutons have intruded sedimentary hosts including shale-sandstone (triassic-jurassic) and sandstone-conglomerate (lower cretaceous). contact metamorphism and hydrothermal alterations are widespread. late alteration assemblage mainly occurs in arkosic sandstones of sangestan formation and includes propylitic, qua...

The Shumagin batholith is part of the Sanak-Baranof plutonic belt in Southwest Alaska that extends approximately 2200km from Sanak Island in the west to Baranof Island in the east. (Hudson, 1979; Hudson et al., 1979; Hill et al., 1980; Bradley et al., 2000; Haeussler et al., 2003). Previous work has indicated that the crystallization ages of the Sanak-Baranof plutons young from west to east. Th...