Mindat Logo

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 District, Santa Rita Mts, Pima Co., Arizona, USA

‡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.





Map Reference: 31°45'47"N , 110°51'54"W

Important Disclaimer: This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.

Switch between Map and Globe


Mineral List:
  • Biotite
  • Bornite
  • Chalcocite
  • Chalcopyrite
  • Hematite
  • 'Hornblende'
  • Magnetite
  • Marcasite
  • Pyrite
  • Quartz
  • Siderite
  • 'Tourmaline'


    12 entries listed. 9 valid minerals.

    The above list contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database!
    This page is currently not sponsored. Click here to find out how you can sponsor this page.


    Mineral and/or Locality
    Google
     
    www.mindat.org Web
    Copyright © Jolyon & Ida Ralph 1993-2008. Jobs in Arizona, USA Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them.Further information contact the Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of hundreds of members and supporters. If you would like to add information to improve the quality of our database, then click here to register.