A fluid inclusion study of the Panguna porphyry copper deposit, Bougainville, Papua New Guinea

Tourmaline of the Mramorny Tin Cluster, Chukotka Peninsula, Russia

“…NaCl), and gas, and this phase separation was responsible for ore deposition. The initial high temperatures (>420°C), an immiscibility of mineralizing fluids, the presence of chloride brines in inclusions, a wide range of homogenization temperatures and salinity, and a combination of various types of inclusions all show the similarity of the ore-forming process in the Mramorny cluster to PTX conditions at typical porphyry-copper deposits (Roedder 1971, Nash 1976, Eastoe 1978, Ahmad & Rose 1980, Bloom 1981, Ruggieri et al 1997, Harris et al 2005, Frikken et al 2005. As seen from the aforementioned evidence, there are several identical characteristic features at the three locations: (1) relation to hydrothermally altered porphyritic rhyolite or brecciation zones in rhyolite; (2) at Sukhoi and Nadezhda, cassiterite was identified, and the Mount Seraya occurrence is characterized by anomalous concentrations of tin in the alluvium of first-order streams; (3) identical minerals are associated with tourmaline; (4) similar chemical compositions of tourmalines are found in different locations, and (5) the ratio Fe 3+ /Fe tot is relatively high in the tourmalines.…”

The physical and chemical evolution of low-salinity magmatic fluids at the porphyry to epithermal transition: a thermodynamic study

“…Alternatively, if a single-phase igneous fluid with low to intermediate salinity (up to $20 wt% NaCl at high P) breaches the two-phase surface at any point on the vapour side of the critical curve it will separate into a somewhat less saline vapour by condensation of droplets of liquid with higher salinity (e.g. Panguna: Eastoe 1978Eastoe , 1982Bingham: Redmond et al 2004). Depending on hydrologic conditions (temperature-pressure-permeability relationships), any vapour existing at some point on the lower-salinity side of the critical curve can depart from the two-phase surface, become physically separated from the liquid, and cool in the single-phase field en route to the surface.…”

“…Hot magmatic fluids, either single-phase (e.g., Rusk et al 2004) or a high-salinity liquid coexisting with a lower-salinity vapour phase (e.g. Roedder 1971;Eastoe 1978;Redmond et al 2004), are the dominant metal-precipitating agents in porphyry-style deposits, although a significant or even dominant proportion of the copper may be precipitated from lower-salinity aqueous fluids below 400°C (Reynolds and Beane 1985). Even cooler (<350°C) aqueous liquids forming high-sulphidation epithermal deposits predominantly have low to intermediate salinity, but stable isotope data show that these fluids also contain a significant or even exclusively magmatic water component (Giggenbach 1992;Rye 1993;Vennemann et al 1993;Kouzmanov et al 2003).…”

Facteurs paramètres dynamique de distribution et genèse des dépôts de columbo-tantalite d Issia centre-ouest de la Côte d Ivoire

“…Au cours de ces dernières années, de nombreuses recherches ont prouvé que rimmiscibilité à l'état fluide peut être responsable de beaucoup de phénomènes géologiques dans les environnements sédimentaires, métamorphiques et magmatiques, entre autres, les transformations métasomatiques (Weisbrod et Poty, 1975;Weisbrod et al, 1976;Lagache et Weisbrod, 1977;Weisbrod, 1980), l'altération et la concentration des métaux dans les gisements de porphyres cuprifères (Roedder, 1971a et b;Denis, 1974;Moore et Nash, 1974;Chivas et Wilkins, 1977;Etminan, 1977;Eastoe, 1978;Ramboz, 1979;Denis et al, 1980;Le Bel, 1980;Wilson et al, 1980), d'autres types de gisements associés aux activités volcaniques (Spooner, 1980) ou magmatiques acides (Kelly et Turneaure, 1970;Landis et Rye, 1974;Rye et Sawkins, 1974;Leroy, 1978;Bray, 1980;Grant et al, 1980;Ramboz, 1980), les gisements métallifères des formations sédimentaires (Roedder, 1976(Roedder, , 1977a et la mise en place des gisements pétroliers.…”