Characteristics And Formation Mechanism Of The Compressed Schistosity Zones And The Control Of The Gold Deposit In Jinchangyu Gold Deposit

Jinchangyu gold deposit which is one of China’s large-scale gold deposits wasundergoing serious resource crisis for long-term exploiting. Recent years deep mineprospecting in Jinchangyu gold deposit shows good prospecting effect. Therefore, it isnecessary to carry out further research work on Jinchangyu gold deposit. Based onprevious work and solid field work, this paper studies and analyzes the characteristicsof the regional geology, the recovery of original rock of the metamorphic in Zunhuarock group, gold-bearing, characteristics and formation mechanism of the compressedschistosity zones and the control of the gold deposit, mineralization model andevaluation of deep prospecting comprehensively. Some understandings are obtainedabout characteristics and formation mechanism of the compressed schistosity zonesand the control of the gold deposit.Following knowledge and results can be obtained through the research.(1) Goldmine is located at the intersection area between the closed fold greenstone belts andmigmatite dome-shaped uplift. The substrate of this mine is Archean metamorphicstratigraphy, which is composed of Qianxi rock group and Zunhua rock group, andsedimentary cover mainly consists of Changcheng group, Jixian group andQingbaikou group.(2) In Jinchangyu gold deposit, original rock of the metamorphicfrom Zunhua rock group is neutral–mafic volcanic rocks which mainly include maficbasalt and the plagioclase hornblendes is one of source of ore.(3) The compressedschistosity zones whose general trend is NNE run through the north and south of themine. The compressed schistosity zones include the schistosity plagioclasehornblendes, the containing-chlorite plagioclase hornblendes, the chlorite schist, thecontaining-sericite chlorite schist, the containing-chlorite sericite schist and so on; thechlorite schist is the main. The strength of schistosity is the strongest in the center ofthe compressed schistosity zones and the strength decreased from the center to bothsides until the massive plagioclase hornblendes appear. The chlorite schist and thecontaining-sericite chlorite schist of the compressed schistosity zones degenerate fromplagioclase hornblendes.(4) The squeeze overturned anticline, syncline which is tilted in the same direction which is in the central anticlinorium in Jinchangyu control thecompressed schistosity zones strictly. In the Zunhua Movement, the prototype of thecompressed schistosity zones formed in the squeeze overturned anticline, synclinewhich is tilted in the same direction. The chlorite schist appeared in rocks and theamphibole retreat into chlorite. In period of Yanshan, due to the impact of thegold-bearing hydrothermal and stress, the chlorite in the chlorite schist sericitized andthe sericite chlorite schist appeared in the compressed schistosity zones. Thecompressed schistosity zones formed further.(5) The compressed schistosity zonescontrol the spatial distribution and size of the gold ore bodies. Gold elements arerelatively abundant where the hub of the central anticlinorium plunges. The size of thegold ore body is small where the hub of the central anticlinorium raises, because thecompressed schistosity zones are eroded and the extension is relatively small.