TABLE OF CONTENTS G. G. PAVLOVA, L. V. GUSHCHINA, A. S. BORISENKO AND A. A. BOROVIKOV
Institute of Geology, SB RAS, Novosibirsk, Russia
E-mail: pavlova@uiggm.nsc.ru
Computer thermodynamic modeling of Ag and Sb behavior in the hydrothermal process in Ag-Sb deposits has been carried out. Parameters of ore-forming fluids, obtained on the basis of fluid inclusion study in minerals of magmatic rocks and ores of tin and silver deposits, were used as original data for modeling. Calculations show that chloride species are the main forms of Ag and Sb transfer in acid highly concentrated chloride solutions. Modeling of formation of Ag- and Sb-bearing mineral parageneses from such solutions indicates their high metal-bearing capacity, an ability to transfer large silver and antimony amounts. Temperature regime is the most important factor of ore deposition, which controls different mineral parageneses, deposited during temperature decrease at the different levels of hydrothermal ore-forming system.
The Ag-Sb and Ag-Pb deposits of economic interest are represented by quartz-siderite veins and vein zones in hydrothermally altered graphitizated terrigenous rocks near intruding granite bodies and sometimes in granites. Ore consists of predominant siderite and sulfosalts, the main component of which is Ag-tetrahedrite, varying amounts of chalcopyrite, pyrite, arsenopyrite, galena, sphalerite, minor Cu-Pb-Sb and Ag-Sb sulfosalts, native Sb and Bi, bismuthinite, stibnite, barite, ankerite, calcite, fluorite and graphite myargyrite, pyrargyrite, stannite. Studies of mineral parageneses recognize 3 main stages of ore-formation: 1) earlier pyrite-arsenopyrite, sometimes with Ni-Co sulfides and sulfoarsenides; 2) quartz-siderite-sulfosalt with Bi-stibnite, zinkenite, jamsonite, chalcostibite, Ag-tetrahedrite, chalcopyrite, bournonite, semsyite...
