The Tamir Molybdenum Event (Western Transbaikal, Russia): the First Data on the Physicochemical Formation Parameters

The Tamir molybdenum occurrence is one of the promising objects of the Selenginsky ore region of Western Transbaikalia. Ore occurrence is a zone of quartz–molybdenite (with beryl) veins and veinlets in leucogranites and granite–porphyries. Thermobarogeochemical methods for studying individual fluid inclusions in quartz and beryl provided the first data on the formation conditions and salt composition of the ore-forming fluids that formed the quartz–molybdenite ores of the Tamir ore occurrence. It was determined that the ores of the Tamir occurrence were formed from relatively weakly saline (~3.4–11.2 wt % NaCl equiv.) CO 2 -containing solutions, with a decrease in temperature in the range from 336 to 215°C, with the main salt components of ore-forming solutions being Ca, Na and K chlorides.