The Geological-geochemical Characteristics And Metallogeny Of Zhijiadi Pb-Zn-Ag Deposit, Lingqiu, Shanxi

Based on the project of "Metallogenic regularity and prediction of Zhijiadi Pb-Zn-Ag deposit in Lingqiu, Shanxi" that National crisismine exploration project management office approved in 2008. As in-depth understanding of epithermal polymetallic mineralization and the establishment of deposit model, this thesis researched on geological characteristics, micro characteristics, and geochemical characteristics (REE, trace elements and stable isotopes), contrasted Faulted hydrothermal filling-type and Cryptoexplosive breccia-type ore-bodies, and studied the sources and metallogeny of Zhijiadi Pb-Zn-Ag deposit.The major achievements as follows:(1)Carried out field investigation of Zhijiadi Pb-Zn-Ag deposit, by observing the geological phenomena of sublevel and drilling, divided two main ore-body types:Faulted hydrothermal filling-type and Cryptoexplosive breccia-type ore-bodies, compared their shape and spatial distribution.(2)Microscopic characteristics and geochemical characteristics of the two types of ore-body were compared by analyzing rock microstructure and X-ray diffraction, it showed that composition, texture and structure of the two ore-bodies of were significantly different. It confirmed the correct classification from the micro point of view between the two.(3) Carried out element content analysis of different sulfide by ICP-MS, Microscope, SEM and EDS, the results showed that there were at least two periods of mineralization in this district, provided an effective theory for the expansion of mine.(4)Attempt of using U-Pb zircon ages in the cryptoexplosive breccia cement, confirmed its metallogenic epoch (129-144Ma).(5)Geochemistry study was carried out on ore-forming rock, the major elements, REE and trace element analysis of quartz porphyry showed that the main features were similar with the S-type granite. Pb isotopes,δ18O,δD, and Lu-Hf isotope analysis showed that the main source area of magmatic rocks was lower crust, and mantle materials mixed.