Iron Cliff prospect (Littleshot prospect; Little Shot Mine; Velvet Mine), Littleshot Camp, Madera Canyon, Old Baldy District, Santa Rita Mts, Santa Cruz Co., Arizona, USA
|Latitude & Longitude (WGS84):||31° 41' 45'' North , 110° 51' 45'' West|
|Latitude & Longitude (decimal):||31.6958333333, -110.8625|
|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: 168, 177.
Drewes, H.D. (1971) Geologic map of the Mount Wrightson quadrangle, southeast of Tucson, Santa Cruz and Pima Counties, Arizona: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-614, 1 sheet, scale 1:48,000.
USGS Mt Wrightson Quadrangle topo map.
Yale Peabody GNIS database (NOTE: this database is derived from USGS 1:24,000 topographic map data).
MRDS database Dep. ID file #10039601, MRDS ID #M050406; and, Dep. ID #10162343, MAS ID #0040230264.
A former underground Cu-Au-Pb prospect with underground workings located in sec. 13, T20S, R14E, just north of Littleshot Camp at an elevation of 6,275 feet, 9 miles W of Mt. Wrightson, about 13 airline miles NNW of Patagonia, on National Forest land. Discovered 1915. The Littleshot Mine could be the same as the Iron Cliff; can't tell from the literature.
Mineralization involves a 5 foot (1.52 meter) wide, iron-stained fault of shear zone in granite. The zone strikes ENE and dips 75ºNNW. It contains streaks of crushed rock or gouge-like material, which on the hanging wall side carries some pyrite and chalcopyrite with a fair amount of gold. On the opposite, or east side of the creek, a tunnel on the same ledge shows much pyrite and galena with a little pyrite and some arsenopyrite on the footwall. The host rocks include the Josephine CAnyon Diorite and the Madera Canyon Granodiorite. Ore control was the shear zone.
Regional trends include tilting and broad open folds in the south and extensive faulting in the north; thrust and normal faulting, shear zones.
Workings include a short tunnel.
; INFO FROM LAND.ST :(1964)
Workings 1 PHYSICAL DIMENSIONS NOT AVAILABLE.
4 valid minerals.
This 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 data will improve over time as more accurate maps and data sets are added.
|Paleocene - Late Cretaceous56 - 100.5 Ma||Early Tertiary to Late Cretaceous granitic rocks|
Porphyritic to equigranular granite to diorite emplaced during the Laramide orogeny. Larger plutons are characteristically medium-grained, biotite +/- hornblende granodiorite to granite. Smaller, shallow-level intrusions are typically porphyritic. Most of the large copper deposits in Arizona are associated with porphyritic granitic rocks of this unit, and are thus named 'porphyry copper deposits'. (50-82 Ma)
|Cretaceous - Jurassic66 - 201.3 Ma||Jurassic-Cretaceous volcanic: interlayered sedimentary and volcanic rocks|
Volcanic: interlayered sedimentary and volcanic rocks
|Cretaceous66 - 145 Ma||Cretaceous plutonic rocks|
Deep-seated to high-level intrusions are included. Many charnockites, anorthosites, and large ophiolites, classified as plutons, are distinguished in the database using the SIGNIF item. Ophiolites were classified as plutons, even where remnants may be extrusive and/or sedimentary.
References for regional geology:
Data provided by Macrostrat.org
Garrity, C.P., and Soller, D.R.,. Database of the Geologic Map of North America: adapted from the map by J.C. Reed, Jr. and others (2005). U.S. Geological Survey Data Series 424 .
USGS compilers. State geologic map data. State Maps.
Geological Survey of Canada. Generalized geological map of the world and linked databases. doi:10.4095/195142. Open File 2915d.