Roadside Mine (Mother Lode Mine; Arizona Rand Gold Mine Inc.), San Francisco District, Oatman District (San Francisco District; Union Pass District), Black Mts, Mohave Co., Arizona, USA
|Latitude & Longitude (WGS84):||35° 13' 9'' North , 114° 28' 59'' West|
|Latitude & Longitude (decimal):||35.21917,-114.48306|
‡Ref.: Wilson, E.D., et al (1934), AZ Bur. of Mines Bull. 137: 104-105; Conrad, J.E., et al (1990), Mineral Resources of the Black Mountains North and Burns Spring Wilderness Study Areas, Mohave County, Arizona, USGS Bull. 1737-C: C7; Gardner, E.D. (1936), Gold mining and milling in the Black Mountains, western Mohave County, Arizona, US Bur. Mines Info. Circ. 6901; USGS 7.5 minute Union Pass topo. map; AZ Dept. Min. Resources (ADMR) Mohave Custom Mill proj. card file; AZ Dept. Min. Resources (ADMR) Frisco Mine-Mine file, Householder map; AZ Dept. Min. Resources (ADMR) Roadside Mine-Mine file; MRDS files #10027945 & 10258818.
A former underground Ag-Au mine located 4 miles East of the Gold Standard mill. Discovered 1915.
Mineralization is the Roadside lode that strikes Northward and dips 33º to 38º W. and occurs within a fault zone in a fan-shaped block of rhyolite, some 32 feet wide at its narrowest or south margin, is in fault contact with granitic gneiss on the East and West. Oreshoot is from 20 to 35 feet wide and 75 feet long on the strike. It consists of irregular stringers and bunches of quartz and calcite in shattered, silicified rhyolite. Ore control was the Black Mountain Detachment breccia. Alteration is chloritization and silicification. Related structure is the Detachment Fault.
Workings include a 100 foot deep shaft (1915-1916) plus some drifting. Production was some 890 oz. Au & 1,734 oz. Ag.
7 valid minerals.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
|Tortonian - Bartonian|
7.246 - 41.3 Ma
|Middle Miocene to Oligocene volcanic rocks|
Age: Cenozoic (7.246 - 41.3 Ma)
Description: Lava, tuff, fine-grained intrusive rock, and diverse pyroclastic rocks. These compositionally variable volcanic rocks include basalt, andesite, dacite, and rhyolite. Thick felsic volcanic sequences form prominent cliffs and range fronts in the Black (Mohave County), Superstition, Kofa, Eagletail, Galiuro, and Chiricahua Mountains. This unit includes regionally extensive ash-flow tuffs, such as the Peach Springs tuff of northwestern Arizona and the Apache Leap tuff east of Phoenix. Most volcanic rocks are 20-30 Ma in southeastern Arizona and 15 to 25 Ma in central and western Arizona, but this unit includes some late Eocene rocks near the New Mexico border in east-central Arizona. (11-38 Ma)
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052.