Polymetal (Ag, Pb, U, Cu, Bi, Zn, F) Adrasman-Kanimansur ore field (Tadzhikistan), and its ore-forming system. I: Geology, mineralogy, and structuralconditions of the ore deposition

Principal features of the geology, mineralogy, and geodynamic conditions of the ore deposition at the Adrasman-Kanimansur ore field, one of the bigges t ore fields in the Central Tyan Shan Mnts., are discussed. This ore field contains a great variety of ore metals (Ag, Pb, U, Cu, Bi, Zn, F), but the silver-base-metal and uranium mineralizations predominate. In the forthcomi ng, second paper, physicochemical, thermobarometric, and geochemical featur es of the ore deposition will be discussed, and the model will be proposed of the hydrothermal ore forming system that has deep roots and complex evol ution path. The ore was deposited due to effervescence of an ascending deep fluids that were mixed with meteoric waters. The temperature of ore deposi tion varies in the interval 120-270 degrees C, solution acidity was pH = 5 +/- 1, and activity of the sulfur and oxygen corresponded to the tripple po int hematite + magnethite + pyrite. The variability of the mineral ore type s relates to the polystage ore deposition. The last depends, in turn, on th e high tectonic activity in the crustal block resulting in the periodic ope ning of the deep seated fluid collectors. These collectors are reservoirs w here ore-bearing fluids are collected, developed, and differentiated. It is proposed that such collectors were distributed at several deep levels, rel ated to the structure and evolution trends of the fluid-magmatic system.