Литосфера (Oct 2017)
Fluid regime of formation and metallogenic features of granitoids Yuzhno-Pomursky Mаssif (Northern Urals)
Abstract
Granitoid massifs of the northern part of the West Tagil structural-formational zone previously had not a reliable geochronological substantiation of age however, some of them are connected with skarn-magnetite deposits. One of such ones is the Yuzhno-Pomursky massif, to which the dedicated copper-iron ore deposit - Tretii Severnyi Rudnik. Authors performed the geological research of the massif, studied the composition of intrusive rocks, and accessory minerals of granitoids. There were determined the contents of petrogenic oxides and petrological-informative elements by ICP-MS; the age of magmatic rocks was determined by U-Pb LA-ICP-MS method in zircons and titanites. Using the microprobe SX-100 it was performed the analyses of the compositions of apatites, amphiboles, magnetites and ilmenites, feldspars and zircons. The studies showed that the Yuzhno-Pomursky massif consists of igneous rocks belonging to the two Silurian complexes - diorite-granodiorite Petropavlovsky and diorite-granite Severorudnichnyi. The characteristic of petrographic features and chemical composition of the intrusive formations is given, the data of their age is provided. The study of the evolution of the fluid regime that accompanied the crystallization of the melt, showed that in the early stages of the fluid has been enriched with chlorine, and the later - fluorine; so accordingly changed the metallogenic orientation of fluid-hydrothermal processes: from skarn-magnetite to gold and rare metal systems. In exocontact aureole of the massif are known ore manifestations and deposits of skarn copper-magnetite ores, mineralized gold-sulfide zones, some points with high content of tungsten. The conclusion about the possibility of the presence at the exocontact of Yuzhno-Pomursky massif not only copper-skarn-magnetite deposits similar to the known Tretii Severnyi, but the gold mineralized zones too is inferred.
