Author Description

A belt of metamorphic core complexes crops out in southeastern California and west-central Arizona in the Basin and Range Province southwest of the margin of the Colorado Plateau (fig. 1). The complexes consist of crystalline rock (commonly mylonitized) below a low-angle detachment fault. Overlying the detachment fault are unmetamorphosed Tertiary sedimentary and volcanic rocks, metamorphosed Mesozoic and Paleozoic sedimentary and volcanic rocks, and Proterozoic and younger plutonic and metamorphic rocks lacking pervasive mylonitic structures. Crystalline rocks below detachment faults in the Rawhide, Buckskin, Little Buckskin, Harcuvar, Harquahala, Little Harquahala, and Granite Wash Mountains have been informally named the Harcuvar metamorphic core complex (Rehrig and Reynolds, 1980), or simply Harcuvar complex, because in some areas it contains unmetamorphosed igneous rocks.