Research On The Source, Natural And Evolutionary Mechanisms Of Mineralization Fluid Of Shihu Gold Deposit In The Taihang Moutains

The study of the ore-forming fluid is a very important aspect of the deposit, the predecessors only discuss the sources of ore-forming hydrothermal mineralization physical and chemical conditions on the ore-forming fluids briefly, but lacking of the following detailed division of mineralization periods inclusions, more lacking of the study of water-rock reaction and the dynamic understanding of fluid evolution. The paper is on the research of the Shihu gold ore-forming fluid origin, character, evolution mechanisms according to the data of isotope, fluid inclusion and major and trace element.1. The paper consider that the hydrothermal mineralization is a process, it is converted from initial magmatic water to late magmatic mixed fluid inclusions according to the H-O isotope and inclusions groups analysis data. Isotope and total sulfur isotope indicate that that the original S of Shihu gold deposit is upper mantle, and sulfide formation temperature is between 750℃-800℃. Pb isotope indicates that it mainly comes from lower crust and only a part of Pb is from upper mantle, moreover it is related to the grade metamorphic crust and assimilation.2. typical section-180 middle 31 line-tells us through the major and trace elements that the Shihu gold mineralization fluid is rich in alkali and silica which is characterized by a lot of potassium and silica alteration; besides it also contains large amounts of Cu, Pb, Zn, Rb,Ba and other elements which forms a large number of polymetallic sulphides. However, the contents of Fe is different in the different sections that can be used as indicator elements. At the same time, In the process of alteration, quality is loss.3. fluid inclusion studies have shown that Shihu Wu gold overall is characterized by low temperature, low salinity and low-density. Hydrogen and oxygen isotopes which indicate W/R ratio and inclusions group analysis shows that the main mineralization of the environment is a weak acid-weak reduction neutral environment.4. After installments and calculation of fluid inclusions we find that both the gas and liquid ingredients or some physical and chemical parameters such as fCO2, fCH4,fH2S,fH2O is not incremented or decremented but fluctuations. Combining with the consideration of potassic stage, we think that Gold fluid is a multi-stage, multi-stage pulse activity.5. Mineralization fluid evolution of Shihu gold depoit has different stages. We have fond a lot of boiling inclusions in the main mineralization stage. After calculating physical and chemical parameters and drawing picture, we think that the main mineralization has two mechanisms and trends:concentrated (fluid boiling) role and dilution, and the coactions of the two mechanisms lead to gold precipitation.