Iron Mask Mine (Iron Mask prospect; McCleary prospect; Littleshot prospect), Jackson Mine group (McCleary group; Old Baldy Copper Mine; Rosa Mine; Hickory; Decatur), Jackson Canyon, Old Baldy Mining District, Pima County, Arizona, USAi

Regional Level Types
Iron Mask Mine (Iron Mask prospect; McCleary prospect; Littleshot prospect)	Mine
Jackson Mine group (McCleary group; Old Baldy Copper Mine; Rosa Mine; Hickory; Decatur)	- not defined -
Jackson Canyon	Canyon
Old Baldy Mining District	Mining District
Pima County	County
Arizona	State
USA	Country

‡Ref.: Schrader, F.C. & J.M. Hill (1915), Mineral deposits of the Santa Rita and Patagonia Mountains, Arizona, USGS Bull. 582: 168, 172.

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.

MRDS database Dep. ID file #10039498, MRDS ID #M050171.

A Cu-Fe prospect/occurrence with underground workings located in sec. 24, T19S, R14E, 2¼ miles south of the McCleary Camp and 1¼ miles south of the Jackson Mine, in Jackson Canyon, at an elevation of 5,170 feet, and 30 miles S of Tucson. Discovered 1915. Owned by Mr. McCleary

Mineralization is the same lens of dark diorite rock as at the Jackson Mine, which is intrusive into the gray granite. The diorite seems also to be intrusive into the rhyolite on the east. The diorite is a dark medium-grained, moderately porphyritic rock composed chiefly of oligoclase-andesinte and dark green hornblende, and it contains considerable magnetite. The vein dips steeply to the north. The host rock unit is the Elephant Head Quartz Monzonite. Microscopic tourmaline occurs in the gangue. There is a large amount of Fe in the veins.

The vein material is about one-third magnetite, one-third chalcopyrite and pyrite, and one-third gangue minerals, principally quartz and siderite in about equal amounts, with a little biotite and hornblende.

The croppings are largely magnetite and other iron oxides. Pyrite was encountered about 25 feet below surface and the copper-bearing minerals at 35 feet. The ore also contains macroscopic black tourmaline in the massive or indistinctly crystalline form, marcasite, bornite, and iridescent hematite. Microscopically the quartz shows medium- to fine, irregular, allotriomorphic, interfingering grains. The chalcopyrite, pyrite and magnetite occur in irregularly forked aggregates and veins as interstitial fillings in the quartz. In places they enclose tourmaline, and seemingly they were among the latest of the minerals to be formed. The presence of the tourmaline indicates also that pneumatolytic action may have been an important agency in the formation of the deposits and that the deposits were probably formed at considerable depth.

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 a 50 foot deep shaft.

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Link to USGS MRDS:	10039498

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