Jerome Grande shaft (Jerome-Grande prospect; Patented claims MS 2643), Hickey Mountain, Yavapai Co., Arizona, USA
|Latitude & Longitude (WGS84):||34° 44' 31'' North , 112° 7' 58'' West|
|Latitude & Longitude (decimal):||34.741943359375, -112.13277435302734|
‡Ref.: Anderson, C.A. & S.C. Creasey (1958), Geology and ore deposits of the Jerome area, Yavapai County, Arizona, USGS PP 308: 154.
Yale Peabody GNIS database (NOTE: this database is derived from USGS 1:24,000 topographic map data).
USGS Hickey Mountain Quadrangle map.
Arizona Department of Mineral Resources Jerome Grande Copper Co. file.
U.S. Bureau of Land Management Mining District Sheet 56.
MRDS database Dep. ID #10027267, MRDS ID #M002673; and, Dep. ID #10186670, MAS ID #0040251198.
A Cu occurrence/prospect with underground workings. Claims extend into sec. 27.
Mineralization was a massive sulfide ore body hosted in the Deception Rhyolite and Grapevine Gulch Formation. Ore control was stratigraphy and igneous activity. Ore concentration was oxidation at near surface. Alteration was chloritization and sericitization.
Area structures include massive sulfide lenses elongate parallel to bedding in metavolcanic rocks. Foliation in metavolcanic rocks trends N10W to N40W.
3 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
1600 - 1800 Ma
|Early Proterozoic metavolcanic rocks|
Age: Statherian (1600 - 1800 Ma)
Description: Weakly to strongly metamorphosed volcanic rocks. Protoliths include basalt, andesite, dacite, and rhyolite deposited as lava or tuff, related sedimentary rock, and shallow intrusive rock. These rocks, widely exposed in several belts in central Arizona, include metavolcanic rocks in the Yavapai and Tonto Basin supergroups. (1650 to 1800 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. 
1600 - 2500 Ma
Age: Proterozoic (1600 - 2500 Ma)
Description: Medium- to coarse-grained, equigranular, hornblende-rich gabbro-norite, gabbro, and gabbro-diorite. Exposed as large bodies throughout central Bradshaw Mountains (zones 2–5). Smaller bodies exposed near Jerome, in the Black Hills (zone 6), especially within Grapevine Gulch Volcanics. Mildly to strongly deformed and metamorphosed in central Bradshaw Mountains. Larger bodies have only localized zones of high strain; smaller bodies are more thoroughly deformed. Undeformed and only mildly metamorphosed in Black Hills. Largest gabbro mass is exposed in zone 2, west of Prescott, and is centered on Sugarloaf Mountain. Compositions range from gabbro-norite to diorite, and include abundant leucogabbro bodies too small to show on map. Zone 2 contains a higher percentage of gabbro-norite than most other zones, and has some of the most primitive chondrite-normalized rare-earth-element (REE) profiles. Zone 3 contains three large gabbro masses. One extends north from Longfellow Ridge to west edge of Big Bug Mesa, and is referred to as the Dandrea Ranch mass, for a locality west of Big Bug Mesa. Another, possibly related to the first, is centered on Bodie mine, west of Crooks Canyon. The last is centered on Salida Spring, east of Prescott. A prominent aeromagnetic high east of Prescott is spatially associated with this mass (Langenheim and others, 2002, fig. 5b). Chemistry of first two bodies is similar, ranging from gabbro-norite, through gabbro, to gabbro-diorite. Wide range in both K/Na and Fe/Mg ratios and no obvious systematic pattern may suggest complex intrusive mixtures in the two bodies. Salida Spring body contains small-scale igneous layers defined by east-striking flow foliation. Both the Salida Spring gabbroic body and the Badger Mountain ultramafic body have distinctive REE patterns with pronounced positive Eu anomalies, suggestive of crystal accumulation of plagioclase. Many small gabbro bodies are exposed in zone 4, the largest of which is at the Blue Bell mine. Chemistry of most bodies is similar and shows little variation. Many gabbro bodies in Jerome area are distinctive by being high Al and plagioclase rich, similar to those in zone 5. Underground samples of gabbro at United Verde mine are notably Al rich, and could represent plagioclase cumulates of leucogabbro, as suggested by their sodic nature and Fe- to very Fe-rich nature
Comments: Early Proterozoic plutonic rocks are widely exposed throughout map area. In order to aid in the discussion of these rocks, the exposures of plutonic and metavolcanic rocks are divided into six zones (zones 1–6, from west to east). These zones are roughly parallel to regional foliation and contain rock units that are similar to one another. The zones are not crustal blocks nor are they necessarily separated from one another by discrete tectonic structures
Reference: DeWitt, E., V. Langenheim, E. Force, R.K. Vance, P.A. Lindberg, R.L. Driscoll. Geologic map of the Prescott National Forest and the headwaters of the Verde River, Yavapai and Coconino Counties, Arizona. Scientific Investigations Map SIM-2996.