WebEl trabajo de Gustafson y Hunt (1975) proporciona una visión más dinámica de un sistema de tipo pórfido cuprífero, en comparación al modelo estático de Lowell y Gilbert (1970), … http://geode.colorado.edu/~skewes/pdf/skewes_atkinson1985.pdf

University of Colorado Boulder

Webveins described in the porphyry Cu literature (Gustafson and Hunt, 1975), and so approach mesothermal levels of formation in the original definition of the term (Lindgren, 1922). The term epithermal is therefore herein only included in the names of deposits formed at shallow crustal levels (epithermal quartz Au-Ag and epithermal banded Webveins described in the porphyry Cu literature (Gustafson and Hunt, 1975), and so approach mesothermal levels of formation in the original definition of the term (Lindgren, 1922). … gary shrum

33-Gustafson and Quiroga G.-1995 PDF Minerals - Scribd

WebThe porphyry deposits are low grade but usually very large in size, as a result of the low grade and size few porphyries support expensive underground mining techniques and most are mined by open ... Webface (Lowell and Guilbert, 1970; Gustafson and Hunt, 1975; Beane and Titley, 1981; Seedorff et al., 2005). Commonly, early Cu-bearing quartz veins with K-silicate alteration are cut by quartz-molybdenite veins, which are cut by pyrite veins with sericitic alteration (cf. Gustafson and Hunt, 1975). In WebLowell and Guilbert (1970), Gustafson and Hunt (1975), Lanier and others (1978), and Titley, (1982). GEOLOGIC FACTORS THAT INFLUENCE POTENTIAL ENVIRONMENTAL EFFECTS Deposit size Tonnage estimates for the 90th, 50th, and 10th percentiles are respectively 19, 140, and 1,100 million metric tons (Singer and others, 1986). Host rocks gary shrum obituary