Evolution of the Mineralizing Fluids and Possible Genetic Links between Miduk Porphyry Copper and Latala Vein Type Deposits, Kerman Copper Belt, South Iran

摘要

The Cenozoic Urumieh-Dokhtar Magmatic Belt (UDMB) of Iran is a major host to porphyry Cu-Mo-Au deposits (PCDs), represented by the world-class Sarcheshmeh deposit and Miduk deposit in the south and the Sungun deposit in the north. Vein type, base and/or precious metal deposits are also common and some are spatially associated with PCDs. Latala and Chahmessi are vein type, base and precious metal deposits in the north and southwest Miduk deposit. The area is covered mainly by Paleocene- Eocene volcanic and pyroclastic rocks of basaltic, basaltic-andesitic and trachy-andesitic compositions, and minor marls and limestones. The volcanic and pyroclastic rocks are intruded by Miocene shallow intrusions of quartz diorite, quartz monzonite and granodiorite compositions. The rocks are host to a set of ore-bearing quartz veins. Mineralization in both the Chahmessi and Latala deposits are controlled by faults and fractures. The role of the ring structures and faults in the distribution of hydrothermal alteration zones and mineralization is important in the Latala deposit. In these veins, euhedral quartz with sulfide mineralization occurs as open space fillings, minor replacement bodies and hydrothermal breccia. The veins consist of quartz, calcite, pyrite, chalcopyrite, galena, sphalerite, bornite and minor sulfosalts, particularly enargite. According to studies based on fluid inclusions in the Miduk porphyry, three types of fluids are responsible for mineralization. Homogenization temperatures and salinity in porphyry-type fluids vary from 566 to 162 degrees C and 61.3 to 1.2 wt% NaCl equiv. For the Latala vein type base and precious metals deposit, homogenization temperature and salinity vary from 380 to 131 degrees C and 10.6 to 0.17 wt% NaCl equiv. The gas phase in fluid inclusions of Latala is dominated by CO2 but also shows the presence of CO and H-2, characterizing reducing conditions associated with ore deposition. The change from lithostatic to hydrostatic regime, boi