Hydrothermal Alteration Zonation and Fluid Late stage 1c hypogene alteration involved the interaction of low-temperature (~120°C) basinal brines with the hematite-ankerite-magnetite mineral assemblage. At the Southern Ridge deposit this process was very intense (ie high fluid flux), therefore resulting in the almost total removal of ankerite and resulting in the increased porosity of the ore. Stage 2 supergene enrichment in the Hydrothermal ore-forming processes in the The experimental metal solubilities for rock-buffered hydrothermal systems, reported by Hemley et al. (1992), provide important insights into the acquisition, transport, and deposition of metals in real hydrothermal systems that produced base metal ore deposits. Water-rock reactions that determine pH, together with total chloride and changes in temperature and fluid pressure, play significant The Prominent Hill iron oxide – Cu – Au deposit Lithology and hydrothermal alteration control the distribution of copper grade in the Prominent Hill iron oxide–copper–gold deposit, Gawler Craton, South Australia (Chapter 2) The copper sulfides at Prominent Hill are hosted in a steeply dipping sedimentary rock package and structurally underlying volcanic rocks likely equivalent to the lower Gawler Range Volcanics (GRV).
This PhD project investigated the mineralogy, zonation and fluid chemistry of the hypogene high-grade iron ore bodies at the Serra Norte deposits at Carajas Brazil which represents the world's largest high-grade (>65% Fe) iron ore resource. These investigations were the first undertaken at Carajas and thus instrumental in defining the P-T-X conditions of hypogene ore formation at this giant Mineral chemistry of ore and hydrothermal The Sossego deposit comprises two major groups of orebodies with distinct styles and intensities of hydrothermal alteration (Carvalho et al., 2005, Monteiro et al., 2005, Villas et al., 2005).This variability likely reflects both different host rocks and different paleostructural levels (Monteiro et al., 2008).The Sequeirinho orebody represents the bulk of resources, with 85% of the ore reserves.What controls high-grade copper mineralisation at Olympic bornite-chalcocite zones largely representing the underground Ore Reserve. Nonetheless, the deposit displays a uniform, vertical and lateral mineralogical zonation pattern. The mappable geological controls on copper grade within the deposit, in order of decreasing importance, are sulphide mineral type and abundance, hematite alteration intensity,
Geochemistry of Hydrothermal Alteration in Volcanic Rocks Silvina Marfil and Pedro Maiza Universidad Nacional del Sur INGEOSUR- CIC de la Provincia de Buenos Aires CONICET Argentina 1. Introduction Hydrothermal alteration is a ch emical replacement of the original minerals in a rock by new minerals where a hydrothermal fluid delivers the chemical reactants and removes the aqueous CREEDE, COMSTOCK, AND SADO EPITHERMAL VEIN DEPOSITS all scales due to well developed spatial zonation within vein and alteration mineral assemblages. (2) Pyrite contents of vein ore and carbonate contents of ore and wall rock principally determine the pH and metal content of water draining mines, mine waste piles, and tailings associated with epithermal vein deposits. Veins thatMINERALOGY AND PETROLOGY OF SKARN DEPOSITSTheir intimate admixture of iron·rich skarn minerals and ore minerals implies that skarns may provide natural examples of the laboratory processes of sulfidation and oxidation. 5. They arc essentially retrogressive; that is, they form with falling tem perature. This feature promotes the fo rmation of mineral assemblages of low variance. Several < facies:t or phases of skarn formation ca n
The pattern of alteration zonation is controlled by either depth or temporal evolution of ore-forming fluids. • A lack of abundant sulfide minerals is probably due to an evaporate origin of ore forming fluids. • The temperature increased during sodic and calcic alteration and mineralization and then decreased. Abstract. Bafq Mining District (BMD) is an iron mineralization province that Magnetic effects of alteration in mineral systemsestimated zonation of magnetic susceptibility inferred from reported modal mineralogy for a typical copper skarn. Table 4 summarizes the differences between alteration assemblages developed around porphyry copper deposits in mafic, felsic and carbonate host rocks. Intense epithermal-style alteration, whether low- or high-Appendix 2: Environmental and Social Impacts of MiningAppendix 2: Environmental and Social Impacts of Mining This appendix is meant to provide a brief review of the literature with regard to environmental and social impacts from mining, as well as key regulatory issues. Key Environmental and Social Impacts Environmental and social impacts of mining have been well-documented and an ample literature exists on this topic. The following discussion