Study On Tectonic Systems And Their Controlling To The Gold Deposits Distribution In The Region Of West Qinling

West Qinling is a very important tectonic mineralization belt with characteristic for gold and nonferrous metal in the west of China. Up to now,a serious of large-middle scale gold deposits being value of industry have been explored, such as Dongbeizhai gold deposit,Dashui gold deposit,Baxi gold deposit and Manaoke gold deposit etc. It is very complex for for the structure in this region, because it locates in the convergent zone of three tectonic units among Qinling Geosyncline-Fold System,SongPan-Garze Geosyncline-Fold System and Yangtze plate. Within the composite orogenic belt that was developed undergoing several different tectonic evolution stages (Jinning,Caledonian,Variscan,Yinzi,Yanshan and Himalayan )and different tectonic regimes ( cracking,collision and nappe-shear),deep fault systems occupy an important position in rock and ore formation.It controlled the formation and time-space distribution of gold deposits. In this area, the typical feature of the gold deposits is that it belongs to strata-bound Fine- disseminated type of gold deposits being the condition of earth s shallow level and low temperature which were formed in the sedimentary rock-ore hosted serious.â… The theory and method of researchGeomechanics has special theory and ways on the analysis of structure and the study of regional metallogenic rule. By the theory and methods of geomechanics,takes the tectonic identification of structural types,divination of tectonic systems,systematic analysis of ore- controlling structures and the relation between structure and gold mineralization as the center,based on amount of geological survey,fully test in laboratory and mathematics-physical simulation experiment,a serious of study was made for the divination of tectonic systems and the rules of ore controlling.â…¡The analysis of regional tectonicIn this paper, the author take the theory of systematic structure as basis and kernel to make research, used many new methods and new ways ,such as measurement of ancient stress .by TEM and Kaiser effect,measurement of magnetic fabrics,measurement of rock' s limited strain,X-ray fabrics,the limited unit methods of metallogenic tectonic stress field and Holographic photoelastic experiment etc., as well as combined with the information of geophysical,geochemical and remote sensing interpretation etc. Based on this study ,the ancient tectonic systems of pre-Yin period were revealed. For the tectonic framework of Imo-Cenozoic era, five set of tectonic systems were divided,they are EW-orientation tectonic system,SN-orientation tectonic system,NE-orientation tectonic system,arcuate-orientation tectonic systems and NNW-orientation tectonic system.Furthermore it were discussed for the deformation featuresequence,tectonic compounding,the history of deformation and development for each different tectonic systems. At last,about the develop process of regional crustal structure movement was discussed. Among all those study, it was emphyasisly study for the arcuate structural systems which took the major controlling to the basic tectonical framework and gold mineralization. By the way, it was reveled for the reguality of tectonic controlling the ore-forming and distribution in the scale of regional tectonic metallogenic zone.â…¢The study of ore controlling structural systems and the rules of tectono-metallogenicBased on the analysis of regional metallogenic geology setting, by the fully and accurate study to the tectonic metallogenic serious of Baxi-Dashui gold deposits. The research was systematically made for the structure of rock-ore controlling of Fine-disseminated type of gold deposits. The author inquired into the syn-metallogenic structural systems, the feature of syn- metallogenic stress field,the condition of metallogenic tectono-dynamics. Furtherly it were researched for the tendency of ore fluid and the mechanics of the fluid migration drived by tectono-force, tried to explore the relation between syn-metallogenic stress field and gold mineralization of fluid' s migration,tried to look for the rule of forming and distribution of gold deposits ( orebodies ) controlled by stress and strain energy within the whole metallogenic process. So it were revealed for the relation between structural activity and mineralization system under the regime of tectono-force,On the basic of such research,the Tectouo-Reformed Type of gold deposits was suggest, as well as the model of tectono-dynamic mineralizing was established.At last ,according to the whole information acquired from the research,the author provides some hints for ore predication and prospecting.