THE CHARACTERISTICS OF TAWUERBIEKE-ABIYINDI PORPHYRYTYPE OF GOLD DEPOSIT

Tawuerbieke-Abiyindi gold field, located in Upper Palaeozoic Tulasu volcanic fault basin, two kilometers to the south of Axi gold deposit, belongs to Yili-Middle Tianshan continental crust plate block of Khazakstan plate. In the ore field, there occurred a monzonite porphyry rock body, within which four groups of primary joints and fissures are developed. The fissures make up a number of belts which control ore bodies. The ore bodies are in single vein, network and lens form. There are four types of ore, i.e., pyrite quartz vein, pyrite carbonate quartz vein, pyrite sericite-quartzite and veinlet-disseminated types. The mineralization can be divided into endogenetic and supergenetic epoches. The former can be subdivided into three metallogenic stages and the second stage is the major one for gold deposition. The mineral association consists of pyrite, native gold, electrum, quartz, chlorite, calcite, dolomite, sericite, muscovite and barite. The wall rock alteration include silicification, sericitization. chloritization and carbonation. The study on H, O and S isotopes and fluid inclusion of quartz vein indicates that the ore-forming fluid is derived from the mixture of magmatic hydrothermal and meteoric water. The mineralization occurred at temperature of 130℃, pressure of 22 MPa, salinity of 1.03%, pHs of 5.8 to 8.8 and oxygen fugacities of -36.7 to -38.8. Form early to late stages, the nature of ore-forming fluid ranged from acidic to alkaline. Based on the above, it is recognized as subvolcanic porphyry gold deposit.