Golden Gate Mine group (Golden Gate Mine; U.S. Grant Mine; Amerco Mine; Fish Mine; Lexington Mine), Rosemont (Rosemont Camp), Helvetia-Rosemont District, Santa Rita Mts, Pima Co., Arizona, USA
|Latitude & Longitude (WGS84):||31° 48' 5'' North , 110° 45' 39'' West|
|Latitude & Longitude (decimal):||31.8013888889, -110.760833333|
|Other regions containing this locality:||Sonoran Desert, North America|
‡Ref.: Schrader, F.C. & J.M. Hill (1915), Mineral deposits of the Santa Rita and Patagonia Mountains, Arizona, USGS Bull. 582: 92, 128, 132.
Galbraith, F.W. & D.J. Brennan (1959), Minerals of Arizona: 50.
Heatwole, D.A. (1966) Geology of the Box Canyon area, Santa Rita Mountains, Pima County, Arizona: Tucson, University of Arizona, M.S. thesis, 70 p.
Keith, Stanton B. (1974), Arizona Bureau of Geology & Mineral Technology, Geological Survey Branch Bull. 189, Index of Mining Properties in Pima County, Arizona: 126 (Table 4).
Niemuth, N.J. & K.A. Phillips (1992), Copper Oxide Resources, Arizona Department of Mines & Mineral Resources Open File Report 92-10: 12 (Table 1).
Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 158, 235.
Arizona Bureau of Mines field notes (1971), vol. 1, no. 2.
Drewes, H.D. (1971) Geologic map of the Sahuarita quadrangle, southeast of Tucson, Pima County, Arizona: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-613, 1 sheet, scale 1:48,000.
USGS Sahuarita Quadrangle topo map.
Arizona Department of Mineral Resources file data.
MRDS database Dep. ID file #10039408, MRDS ID #M050041; and, Dep. ID #10283576, MAS ID #0040190233.
A former small underground Au-Ag-Pb-Zn-Cu mine group located in the SE ¼ sec. 1 & the NE ¼ sec. 12, T.19S., R.15E. (Sahuarita 15 minute topo map), 2½ miles SW of Rosemont, and 28 miles SE of Tucson. It lies along the ridge running northwestward from Deering Camp and in the valley west of the ridge. Produced 1925-1969. Owned at times, or in part, by Holliday; Ramsey; Hunnell; Halbert; Nail; E.C. Ranney; and the Arizona Mining & Refining Co.
Mineralization is irregular quartz stringers, lenses, and bunches containing partly oxidized base metal sulfides in fissure veins and replacements along thrust-fault contacts of Paleozoic limestone and Cretaceous sedimentary formations. Galena in small stringers in sheared limestone - shale. Ore apparently in silicious pockets, veinlets, and films on slickensides. Ore is 4.57 meters thick. Host rock units are the Willow Canyon Formation conglomerate and siltstone, and the Martin Formation Dolomite.
A seeming depositional contact of dull-red sandy shale and overlying limestone dips 45ºE. Along this contact movement has produced a shear zone about 15 feet wide composed of shattered altered limestone and sandy shale. In this zone, which is heavily iron-stained, occur stringers and bunches of galena and copper carbonates in films along slickensided surfaces. Free gold can be obtained by panning almost any of the more heavily iron-stained croppings, or from the siliceous pockets at the surface, which show considerable limonite and cerussite.
Local structures include thrust and normal faulting, fracture zones, homoclinal. Regional trends include tilting and broad open folds in the south and extensive faulting in the north.
Workings include numerous small shafts, including a 49 foot incline, tunnels, adits and open cuts. Worked sporadically from the 1880's to 1969. Produced some 200 tons of ore averaging about 1 oz. Au/T, 3 oz. Ag/T, 4% Pb and minor Zn & Cu.
5 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
|Gelasian - Burdigalian|
1.806 - 20.44 Ma
|Pliocene to middle Miocene deposits|
Age: Cenozoic (1.806 - 20.44 Ma)
Description: Moderately to strongly consolidated conglomerate and sandstone deposited in basins during and after late Tertiary faulting. Includes lesser amounts of mudstone, siltstone, limestone, and gypsum. These deposits are generally light gray or tan. They commonly form high rounded hills and ridges in modern basins, and locally form prominent bluffs. Deposits of this unit are widely exposed in the dissected basins of southeastern and central Arizona. (2-16 Ma)
Comments: In dissected basins of southeast and central Arizona
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.