many of which contain very little copper. Examples of porphyry molybdenum deposits are the Climax, Urad, Mt. Emmons, and Henderson deposits in central Colorado; the White Pine and Pine Grove deposits in Utah; the Questa deposit in northern New Mexico; and Endako in British Columbia. The US Geological Survey has classed the Chorolque and Catavi tin deposits in Bolivia as porphyry tin deposits. Some porphyry copper deposits in oceanic crust environments, such as those in the Philippines, Indonesia, and Papua New Guinea, are sufficiently rich in gold that they are called copper-gold porphyry deposits. References Dennis P. Cox, 1986, "Descriptive model of porphyry Cu," in Mineral Deposit Models, US Geological Survey, Bulletin 1693, p. 76, 79. Michael L. Zientek, et al., 2013, Porphyry copper assessment of Southeast Asia and Melanesia, US Geological Survey, Scientific Investigations Report 2010-5090-D. Economic geology Copper