The Study On Ore-Field Structures Of Anqing Yueshan Copper-Iron Deposits, Anhui Province

"Yueshan copper-iron ore field" is located in the Anqing -Guichi ore-concentrated area, in the Middle-lower Yangtze River Cu-Fe mineralization belt. Tectonic location is in the middle of lower Yangzi platform fold belt, south of the Dabie orogenic belt, in the near west is huaiyang ancient land, yangtze river is in the south of it. In the environment, strong extrusion and contraction of the Mesozoic Era control the structure effects, magmatic activities and mineralization.Based on previous material and research results ,with own field work ,this paper make a systemic and detailed consolidation of the ore field structural forms in the research area. In combination with regional materials, established structural evolution in this area, clear the relationship between structures and mineralization. The main comprehensions are as follow:1. Clear the time relationship between structures and mineralization Before the metallizing period, the main structures are NE face folds, near NS face and near EW face conjugate shear cracks, and the the surrounding rock folds which caused by heat of the diagenetic process. The Metallizing period is behind the formation of magmaticbody in early Yanshanian ,during the period main structures are the former structures'development and progressive deformation. After the metallizing period the structures, including the near NS face and NW face faults and thrust faults, destroy the ore deposits.2. Clear the spatial relationship between structure and mineralization In the ore field, the fractures of NE face ,near NS face and near EW face are the channels of magma's invasion. The collapse between the stratums in pitch end of NE face fold provides the space for the. The closest relations with ore's host is the contact zones between magmaticbody and the surrounding rock .The main locations that hosting ores are in the folds, and skarn in the contact zones.3. Find out the hosted stratums of ore-deposits, in the ore field deposits have a certain "level control " nature in spatial . The copper iron deposits in the ore field distributes in and near the contact zones between yueshan group gypsum carbonate and the diorite. Carbonate strata of active chemical properties, can easily occur interlayer stripping and crushing under tectonic stress, then form some spaces for ores and magmaticbody. Silty sandstone in tongtoujian group with inactive chemical properties, play a shielding effect and curb the ore-forming fluid's runaway and lost.