Volcanic and intrusive history of the Pine Grove porphyry molybdenum system, southwestern Utah

Palaeoproterozoic porphyry Cu–Au, intrusion-hosted Au and ultramafic Cu–Ni deposits in the Fennoscandian Shield: Temporal constraints using U–Pb geochronology

“…Richards (2011a) discussed the source of metals and sulphur in porphyry systems and, for a majority of the deposits a mantle source for Cu, S and to some extent, Mo has been suggested (cf. Audétat, 2010;Field, 1966;Keith et al, 1986;Pettke et al, 2010;Westra and Keith, 1981). If input of mantle material continued at depth, it may not only have contributed heat during partial melting, but also endowed the partial melt with metals and sulphur, although contribution from re-melted basement cannot be excluded.…”

Major-element, trace-element, and volatile concentrations in silicate melt inclusions from the tuff of Pine Grove, Wah Wah Mountains, Utah

“…In addition to the data listed in Tables 4 and 5, we also analyzed a sample of the "upper unit" that was welded during emplacement of an overlying trachybasalt, shortly after deposition of the tuff of Pine Grove (Keith et al, 1986). The matrix is dense and glassy, as opposed to most of the Pine Grove tephras, which contain matrix that has been altered to friable clay.…”

“…The geology of these volcanic rocks, found within the Miocene Blawn Formation (Abbott and others, 1983), has been described in detail by Keith (1982), Keith and others (1986), and Keith and Shanks (1988). The analyzed samples were collected by the first author during May 1993 with help from the second author and Dr. Jeffrey Keith of Brigham Young University.…”

“…Roedder (1984) provides a complete introduction to melt inclusions and their analysis. Keith et al (1986) divided the tuff of Pine Grove into an "air fall unit" of Plinian fallout tephra and three overlying pyroclastic-flow units: the "basal unit", "pink unit", and "upper unit." Other volcanic rocks associated with the Pine Grove system include rhyolite domes extruded subsequent to the pyroclastic eruptions, cobbles of which are found in a conglomeratic layer that overlies the eruptive sequence.…”

Petrography, Geochemistry and Petrogenesis of Late-Stage Granites: An Example from the Glen Eden Area, New South Wales, Australia

“…High-level emplacement of the Glen Eden Granite, along with the presence of crenulate quartz layers and parting veins indicate low viscosity of the melt.  By decreasing the solidus temperature of the magma, the assimilation ability of the magma may be increased (Keith and Shanks, 1988).  Due to the decreased solidification temperature of the melt, F-bearing magmas may show extreme differentiation.…”