Specimen Number4-8-001Alternate NumberM-1CommentsOxidized, garnetized limestone, Mississippian age. The southern limit of the Morenci pit is in the Paleozoic sedimentary units which display the spectacular contact metamorphic effects first described by Lindgren at the turn of the century. This specimen is from the Modoc limestone that is intruded by the quartz monzonite porphyry and granite porphyry that produced the deposit. Now an assemblage of garnet, epidote, siderite, magnetite, and hedenbergite, and perhaps pyrite and chalcopyrite. Now oxidized with the formation of jasper, hematite, and limonite, as well as late-stage quartz + calcite veinlets. Grade is 0.015% Cu, with Mo 0.01%. Material like this occurring below that zone of oxidation and more mineralized accounted for some of the early high-grade ores shipped from here.In Teaching CollectionNoMineral(s)epidotegarnetmagnetitequartzRock NameskarnDistrictCopper MountainMineMorenciExternal LinkMindatGeo-LocationundefinedSub-LocationundefinedDeposit TypePorphyry CopperGeo-Coords[1] Reference MaterialACL-173: Anzalone, S.A., Beane, R.E., Davis, S.R., Graybeal, F.T., Guilbert, J.M., Oakley, C.A., Titley, S.R., and West, R.M., org., 1979, Society of Economic Geology Field Conference on Tucson-Area Porphyry Copper Deposits, Tucson, AZ, May 3-6, 1979, 205 p.
4-8-001: skarn - Copper Mountain District - Morenci Mine. Franklin College Collections, accessed 16/11/2025, https://digitalcollections.franklin.uga.edu/nodes/view/31462