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Gila Monster Mine, Jaynes, Amole District, Tucson Mts, Pima Co., Arizona, USA

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Latitude & Longitude (WGS84): 32° 17' 46'' North , 111° 7' 14'' West
Latitude & Longitude (decimal): 32.29611,-111.12056
GeoHash:G#: 9t8zxrk6r
Locality type:Mine
Köppen climate type:BSh : Hot semi-arid (steppe) climate

‡Ref.: Ashley, R.P. (1974), Field Examination (Gila Monster Mine).

Arizona State Land Department Mineral Lease List (1979) – lease 3 49164.

Rocks & Minerals (1988): 63: 327.

Rocks & Minerals (1989): 64: 58.

Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd. ed.: 225, 374.

MRDS database Dep. ID file #10039672, MRDS ID #M050626; and, Dep. ID #10283209, MAS ID #0040190634.

A former small underground Pb-Zn-Cu mine located in sec. 13, T13S, R12E, on the NW periphery of Tucson.

Mineralization is a contact metasomatic deposit hosted in the Tucson Mountains chaos unit with ore in veins and pods. Alteration is argillitic. The ore body is 2 meters wide, strikes N65E and dips 58S.
The vein seems to be sheared-looking. The western margin of the limestone block (outcrop 20-30 meter diameter), forms the hanging wall. Workings are in brecciated andesite with soft pale green argillic matrix. One zone looks like a 2 meter wide zone of irregular stringers and pods of specular hematite plus quartz, plus dark green chlorite with scarce sphalerite, Cu silicate, and galena.

Workings include 2 shafts 10 meters apart.

Field observations: This mine is now relatively inaccessible due to the encroachment of the city of Tucson and private property. The road to the mine area is similarly blocked and access is only by permission of the property owners where the public road ends and an approximate 1 mile (1.6 km) hike.

Regions containing this locality

Sonoran Desert, North America

Desert - 1,136 mineral species & varietal names listed

Select Mineral List Type

Standard Detailed Strunz Dana Chemical Elements

Mineral List

8 valid minerals.

Detailed Mineral List:

Formula: PbCO3
Reference: Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 225.
'Chlorite Group'
Reference: MRDS database Dep. ID file #10039672, MRDS ID #M050626.
Formula: Pb2Cu(CrO4)(AsO4)(OH)
Reference: Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 225.
Formula: PbS
Reference: MRDS database Dep. ID file #10039672, MRDS ID #M050626.
Formula: Fe2O3
Reference: MRDS database Dep. ID file #10039672, MRDS ID #M050626.
Formula: ZnCO3
Reference: Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 374.
Formula: ZnS
Reference: MRDS database Dep. ID file #10039672, MRDS ID #M050626.
Formula: Zn2SiO4
Reference: Rocks & Min.:63:327 & 64:58.
Formula: Pb(MoO4)
Reference: Anthony, J.W., et al (1995), Mineralogy of Arizona, 3rd.ed.: 225.

List of minerals arranged by Strunz 10th Edition classification

Group 2 - Sulphides and Sulfosalts
Group 4 - Oxides and Hydroxides
Group 5 - Nitrates and Carbonates
Group 7 - Sulphates, Chromates, Molybdates and Tungstates
Group 9 - Silicates
Unclassified Minerals, Rocks, etc.
'Chlorite Group'-

List of minerals arranged by Dana 8th Edition classification

Group 2 - SULFIDES
AmXp, with m:p = 1:1
Anhydrous Compound Phosphates, etc·, Containing Hydroxyl or Halogen
Group 51 - NESOSILICATES Insular SiO4 Groups Only
Insular SiO4 Groups Only with cations in [4] coordination
Unclassified Minerals, Rocks, etc.
'Chlorite Group'-

List of minerals for each chemical element

H FornacitePb2Cu(CrO4)(AsO4)(OH)
C CerussitePbCO3
C SmithsoniteZnCO3
O CerussitePbCO3
O FornacitePb2Cu(CrO4)(AsO4)(OH)
O HematiteFe2O3
O SmithsoniteZnCO3
O WillemiteZn2SiO4
O WulfenitePb(MoO4)
Si WillemiteZn2SiO4
S GalenaPbS
S SphaleriteZnS
Cr FornacitePb2Cu(CrO4)(AsO4)(OH)
Fe HematiteFe2O3
Cu FornacitePb2Cu(CrO4)(AsO4)(OH)
Zn SmithsoniteZnCO3
Zn SphaleriteZnS
Zn WillemiteZn2SiO4
As FornacitePb2Cu(CrO4)(AsO4)(OH)
Mo WulfenitePb(MoO4)
Pb CerussitePbCO3
Pb FornacitePb2Cu(CrO4)(AsO4)(OH)
Pb GalenaPbS
Pb WulfenitePb(MoO4)

Regional Geology

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

Quaternary - Miocene
0 - 23.03 Ma

ID: 3185380
Cenozoic sedimentary rocks

Age: Cenozoic (0 - 23.03 Ma)

Lithology: Sedimentary rocks

Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

Ypresian - Campanian
47.8 - 83.6 Ma

ID: 2745161
Early Tertiary to Late Cretaceous volcanic rocks

Age: Phanerozoic (47.8 - 83.6 Ma)

Stratigraphic Name: Williamson Canyon Volcanics

Description: Rhyolite to andesite and closely associated sedimentary and near-surface intrusive rocks; commonly dark gray to dark greenish gray or greenish brown. In the ranges west of Tucson, this unit includes thick welded ash-flow tuffs. Volcanic rocks of this unit are inferred to be derived from vents and volcanoes above magma chambers that solidified to form the granitic rocks of map unit TKg. These rocks are restricted to southeastern Arizona except for a small outcrop near Bagdad. (50-82 Ma)

Comments: Related, broadly, to unit TKg Original map source: Arizona Geological Survey, DI-8 Geologic Map of Arizona, Digital Spatial data for the Geologic Map of Arizona, v. 3.0, edited by S.M. Richard and S.M. Kneale, 2002, 10 p., 2 DOS HD disks. Arc/INFO export file (.e00) format, scale 1:1,000,000.

Lithology: Major:{rhyolite,dacite,andesite}, Minor:{clastic}

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. [133]

Data and map coding provided by, used under Creative Commons Attribution 4.0 License

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