Road Log from Bagdad, Arizona, to Prescott, Arizona: 66.8 miles
Published:January 01, 1987
0.0 Copper Plaza in Bagdad, Arizona. Proceed east on Arizona Highway 96 toward Hillside, Arizona.
0.4 Turnoff to the right to the Bruce mine. Outcrops ahead, on the left, and for the next one-half mile are Hillside Mica Schist intruded by Lawler Peak Granite.
1.0 Roadcut in Hillside Mica Schist intruded by Early Proterozoic foliated granodiorite.
1.2 Small creek from below the Cowboy mine enters Bridle Creek on the right. Outcrops are of dark metabasalt of the Bridle Formation (Anderson and others, 1955). Light-colored rocks are intrusive and extrusive metarhyolite. Roadcuts 0.4 miles ahead in light felsic metavolcanic rocks on the right, dark mafic metavolcanic rocks and Hillside Mica Schist on the left.
1.8 Eastern margin of of metavolcanic belt. Roadcuts in Hillside Mica Schist intruded by aplite-pegmatite.
2.3 Large roadcut contains Hillside Mica Schist intruded by numerous sills and dikes of aplite-pegmatite.
3.4 Tertiary fanglomerate in roadcut. Large dike of aplite-pegmatite projects across the highway. Outcrops ahead about one-quarter mile on the left are light aplite-pegmatite intruded by tan-weathering, ocher-stained, strongly jointed Lawler Peak Granite. On the right are outcrops of strongly jointed Lawler Peak Granite.
4.3 Junction of Arizona State Highways 96 and 97. Arizona State Highway 91 turns off to the right and connects with U.S. Highway 93 to Wickenburg and Phoenix. We continue along Arizona Highway 96 straight ahead through the roadcuts of Lawler Peak Granite. Road narrows through these roadcuts; please drive carefully. Most of the roadcuts are in Lawler Peak Granite, but some aplite-pegmatite
Figures & Tables
Proterozoic Ore Deposits of the Southwestern U.S.
This field conference of the Society of Economic Geologists, held in conjunction with the 1987 Annual Meeting of the Geological Society of America in Phoenix, Arizona, investigates various Proterozoic ore deposits in southeastern California and western and central Arizona. The trip starts in Las Vegas, Nevada, and ends in Phoenix, Arizona. Although Proterozoic ore deposits and geology are emphasized, the field trip traverses a variety of tectonic provinces, each containing ore deposits of various ages. Many geologic features and ore deposits that are not Proterozoic in age will be discussed during the course of the trip, but no stops will be made to investigate any of these, features.
The morning part of the trip starts in the Mesozoic foreland fold and thrust belt of Nevada and southeastern California, goes just east of the Mesozoic batholith belt of California, and ends in crystalline basement containing Early and Middle Proterozoic metamorphic and plutonic rocks. Within this basement is exposed the Middle Proterozoic Mountain Pass Carbonatite deposit, the largest source of rare-earth elements in the world. The Mountain Pass Carbonatite will be the focus of our morning stops.
The afternoon part of the trip crosses Early Proterozoic high-grade metamorphic rocks and plutonic rocks east of Mountain Pass. Ore deposits noted along the afternoon portion of the trip include middle Tertiary epithermal, gold-rich veins at Searchlight, Nevada, and disseminated gold deposits in Tertiary volcanic rocks near Hart Peak in the New York Mountains. The trip continues across the Colorado River trough along the border of California and Arizona, where crystalline basement and its cover of Tertiary volcanic rocks and plutons have been greatly extended along listric normal faults and low-angle detachment faults. The afternoon part of the trip ends in Oatman, Arizona, a district famous for its middle Tertiary epithermal, gold-rich deposits. The ore deposits at Oatman will be the subject of a slide show and talk after supper on the first night of the trip.
The first day ends with an evening drive across a middle Tertiary volcanic pile near Oatman. The first night will be spent in Kingman, Arizona.
Assemble at the Las Vegas Convention Center, south of the Hilton Hotel. Take any main street south to Tropicana Avenue. Turn west on Tropicana, past the Las Vegas Strip, and continue to Interstate Highway 15. Turn south on Interstate 15 toward Mountain Pass, California. Mileage starts at 0.0.