Description:
The Bouse Hills are located in west-central Arizona (Fig. 1) and are within the Basin and Range
physiographic province of the Southwest. The Bouse Hills consist of four rock assemblages (Fig. 2), as
follows: (1) Proterozoic crystalline rocks, (2) moderately to steeply tilted Oligocene(?) to lower Miocene
volcanic and sedimentary rocks, (3) a Miocene pluton and related dikes, and (4) flat-lying to gently tilted
Miocene volcanic and minor sedimentary rocks. Assemblages (1) and (2) were tilted by early Miocene
rotational normal faulting that was widespread in the Basin and Range province (Spencer and Reynolds,
1989). In the Bouse Hills, tilting was probably related to movement on the Plomosa detachment fault
which projects beneath the Bouse Hills from the west (Scarborough and Meader, 1989). Manganese and
barite mineral deposits are mineralogically distinct, and fluid-inclusion data indicate that they were
derived from aqueous fluids with different salinities. These deposits are confined to the Miocene volcanic
and sedimentary rocks.
This report includes a geologic map of the Bouse Hills at a scale of 1:24,000 (plate 1), descriptions
of rock units (Appendix 1), and a stratigraphic correlation diagram (Fig. 3). Also included are
descriptions of mineral deposits (Appendix 2) and a geologic map of some small hills northwest of the
Bouse Hills (Fig. 4).
( 21 pages)