%0 Journal Article
%T Fluid Evolution of the Magmatic Hydrothermal Porphyry Copper Deposit Based on Fluid Inclusion and Stable Isotope Studies at Darrehzar, Iran
%A B. Alizadeh Sevari
%A A. Hezarkhani
%J ISRN Geology
%D 2014
%R 10.1155/2014/865941
%X The Darrehzar porphyry Cu-Mo deposit is located in southwestern Iran (~70£¿km southwest of Kerman City). The porphyries occur as Tertiary quartz-monzonite stocks and dikes, ranging in composition from microdiorite to diorite and granodiorite. Hydrothermal alteration and mineralization at Darrehzar are centered on the stock and were broadly synchronous with its emplacement. Early hydrothermal alteration was dominantly potassic and propylitic and was followed by later phyllic and argillic alteration. The hydrothermal system involved both magmatic and meteoric water which were boiled extensively. Copper mineralization was accompanied by both potassic and phyllic alterations. Based on number, nature, and phases number which are available in room temperature, three types of fluid inclusions are typically observed in these veins: (1) vapor rich, (2) liquid rich and (3) multi phase. The primary multiphase inclusions within the quartz crystals were chosen for microthermometric analyses. Early hydrothermal alteration was caused by high-temperature, high-salinity orthomagmatic fluid and produced a potassic assemblage. Phyllic alteration was caused by high-salinity and lower-temperature orthomagmatic fluid. Magmatic and meteoric water mixtures were developed in the peripheral part of the stock and caused propylitic alteration which is attributed to a liquid-rich, lower temperature. 1. Introduction Due to their low metal grade and very large volume, porphyry-type deposits are described as disseminated and mineralization is, to a great extent, controlled by fractures and faults. Porphyry copper deposits are formed where magmatic-hydrothermal fluids are expelled from a crystallizing magma [1, 2] and initiated by injection of oxidized magma saturated with S- and metal-rich, aqueous fluids from cupolas on the tops of the subjacent parental plutons. The sequence of alteration-mineralization is principally a consequence of progressive rock and fluid cooling caused by solidification of the underlying parental plutons and downward propagation of the lithostatic-hydrostatic transition [3]. Cooling, depressurization, and reaction between the fluids and the wall rocks cause metals to precipitate in and around the fractures, forming veins with alteration envelopes. Alteration assemblages and associated mineralization in porphyry ore deposits develop from huge hydrothermal systems dominated by magmatic and meteoric fluids [4, 5]. Porphyry Cu systems host some of the most widely distributed mineralization types at convergent plate boundaries including porphyry deposits centered
%U http://www.hindawi.com/journals/isrn.geology/2014/865941/