Genetic Mineralogy And Prospecting Mineralogy Of The Liubagou Gold Deposit In Inner Mongolia, China

Liu Bagou gold deposit is a typical deposit characterized by largely potash feldspathization, lying in the north margin of North China Craton. Based on sufficiently the realization of the metallogenic settings, this paper has analyzed the sources of the ore fluids and the regularity of the mineralization enrichment by the studies of the genetic mineralogy and prospecting mineralogy on the major gold-bearing minerals such as quartz, pyrite and K-feldspar, and the prospective prognosis in depth was proposed.The pyroelectricity of pyrite shows N type conductivity, and the forming temperature is mostly between 310 and 330 Centidegree. The cell parameters a0 is between 0.54167 and 0.54214, slightly greater than theoretical value. The cell parameters a0 value increased gradually with depth, and the a0 value is an obvious positive correlation with the Au content of the host rock. The pyrite is characterized by enrichment of Mo and Pb, and a loss of Rb,Zr,Nb and Th. The low content of As and Se is an important typomorphic characteristic.The thermoluminescence curves of quartz are characterized by mostly unimodality and a little bimodality, and the integrated intensity is low. The thermoluminescence temperature intervals of quartz are T1(160～220℃)and T2(220～280℃), and most of intervals are T2. The cell parameters of quartz are slightly greater than theoretical value, decreasing gradually with depth. The quartz concentrates Mo, Pb, As, Sr and Ba, including that the concentration of the total of Mo, Pb and As is a positive correlation with the Au content of the host rock. Higher Sr and Ba contents in quartz shows that the potash feldspathization and water-rock interaction accurred between ore-forming fluids and wallrocks.The K-feldspar is between intermediate microcline and maximum microcline or maximum microcline, and the degree of order of K- feldspar in Liu Bagou is higher than that in Ha Damengou. The Or content in the K- feldspar being close to mineralization is between 92.2% and 96.2%, and the Ab content is between 3.8% and 7.8%, which is nearly the same as that in Ha Damengou. The REE characterisitics of pyrite, quartz and K-feldspar are nearly the same,and the patterns are the same as that of granitic pegmatite vein of Da Huabei. The REE characterisitics of the ore-forming fluids show that Eu positive anomaly obviously, with REE patterns demonstrating a right inclined curve with slightly LREE enrichment,suggesting ore-forming fluids are at high temperature and relatively reductive. The metallogenic type is the mesothermal-hypothermal gold deposit. The postmagmatic hydrothermal fluid may make an impact . Furthermore, the potash feldspathization played a crucial role in the enrichment of the Au mineralization.Through the studies on the typomorphic peculiarities of pyrite, quartz and K-feldspar, it is inferred that the Middle Eastern part of No. 313 Vein is the key prospecting area. The exposed position of Ore body is close to or reaching alkali metasomatism zone, with the upper part of the hydrogen and silicified zone eroded. In contrast with the geological condition of Ha Damengou, it is very possible to find an alteration type gold deposit in the deep region.