THE GEOLOGICAL CHARACTERISTICS OF JIUSHISANGOU GOLD DEPOSIT

Jiushisangou gold deposit is located in the northeast of Yanbian synclinorium-the east part of Duhuangzi-Wangqing Mesozoic continental volcanic block basin. Mesozoic volcanic rocks broadly spread in this area. Pb isotope from quartz diorite porphyry shows that the tectonic setting of magmatism was the late period of orogenic activity (reversion orogenic belt period) in the continental margin(original arc). The content of ΣREE for the magmatic rocks is on the low side(56.86×10^-6~118.02×10^-6). The chondrite-normalized REE patten are slightly right-dipping flat curve, without europium anomaly. In the illustration of (Sm/Eu)_S/(Sm/Eu)_N vs Sm,all kinds of rocks and ores distributed in the same level time and showed the same magmatic source derived from upper mantle. Based on the relation of (Yb)_N and (Ce)_N and the type of REE distribution,these magma was consisted of eclogate and garnet clinopyroxenite. The orebody occured in the inner and outer contact zone of quartz diorite porphyry. The main orebody occured in breccia of inner contact zone. Orebody was controlled by the fault nearly S-N striking. Potassium metasomatism is the main alteration of wallrock. Orebodies occur in pyrite phyllic alteration zone. Gold and polymetal sulfide fill in the fracture of pyrite phyllic altered zone and form veinlet-disseminated ore. Based on the research in geochemical features of S isotope and REE,we determine that metallogenic materials were derived from quartz diorite porphyry,ore-forming fluid was K-rich gas-water solution,mineralization carried out under the condition of higher S isotopic fugacity and the temperature of 220~120℃. To sum up,Jiushisangou gold deposit belongs to post magma of low-to-moderate temperature hydrothermal gold deposit related to quartz diorite porphyry.