Scales pluton
Scales pluton
Middle Jurassic, ~167-168 Ma
Hornblende gabbro and quartz diorite east of Sly Creek Reservoir, north of Highway 49. This pluton has zircon U-Pb ages of ~167-168 Ma (Saleeby and others, 1989b; Day and Bickford, 2004). The Scales pluton intrudes both the Slate Creek and American River terranes across the Slate Creek thrust, constraining the timing of amalgamation.