| West-QinLing metallization belt take to be placed in the very special tectonic background, have good mineral-forming condition and great prospection potential. Although prospector have founded some gold-ore deposits to some extent in some gold metallization concentrate area, such as LiZiYuan, LiMin, XiCheng,etc, among these deposits, most are located in the earth's surface, less in underground. With continuously prospect work, the prospection are more difficulty, at the same time, the resources of most of mine have nearly dried up, it need to look for new resources. In addition, single geological prospection plan which only prospect certain type ore or deposit under the planned economy, lacking macroscopic and systemic research, lacking contact research between different type ore and different mine, cause the cognition is not perfect. Therefore, the purpose of this work primarily is establish metallization mode and find direction of prospection and do prospect work in new prospect area and old prospect area, basing metallization law and metallization characteristic of the gold mine and analyse of geological evolution.The research method of this work is: survey geological section to understand the framework of tectonics; analysis geology process and study region metallization function by new theories and new cognition; establish metallization mode and find direction of prospection basing synthesize research and investigation of the deposits.The research results is as followed: (i) The west QinLing had grown rift at Devonian period in the HaiXi movement, which produced exhalation of the hot water of bottom of sea, forming sedimentation-type lead-zinc ore layer and gold-hosted clastic sediment; (ii) At the end of Permian period in the YinZhi movement, collision orogeny produced a series of nappe, accompany with lots of magma activity, not only reformed the layer of formative lead-zinc ore but also made the gold element activate and gather from the geologic strata, and the gold mine come into being in the area; (iii) In the YanShan movement , Pacific Ocean plate subducted from south-east to west-north, which producedtectonic hydrotherm event of characteristic of fracture and granite activity, and made the gold element in the structure zone activate and transfer which deposite in the enlarge structure or reform pre-orebody.The area's gold metallization primarily concentrate in LiZiYuan area, LiMin area, and XiCheng area etc. The type of gold metallization in the area is divided three types: fracture type, fracture-alteration type and Quartz-vein type. The evolution of the eastern region of West-QinLing have four process: JiaLiDong period, HaiXi period, YinZhi period, YanShan period. In the JiaLiDong period, it produced the main ore-resource layer-LiZiYuan group greenchist. In the HaiXi period, it produced XiCheng lead-zinc deposits and XiCheng ore-resource layer-XiHanShui group clastic, and produce another gold ore-resource layer-LiBa group clastic in the area of LiMin. In the YinZhi period, reformed the lead-zinc deposits, at the same time, produced XiCheng fracture-type gold mine, LiZiYuan Quartz-vein type gold mine and made fracture-type gold mine in the area of LiMin pre-gather. In the early of YanShan period, LiMin fracture-type gold mine is produced, and following Cu, Mo poly-metallic ore deposit produced with the end of the magma activity .In a word, gold metallization in the eastern region of West QinLing primarily distribute in the LiZiYuan group greenchist, LiBa group clastic and XiHanShui group nhyllite; gold metallization body mainly location in the fracture zone and inside and outside contact zone of invading rockbody of YinZhi period and YanShan period, and fracture type, fracture-alteration type orebody location outside of invading rockbody in the range of 1 -5 thousand; Whether magma reason or structure reason, the gold mine is all controlled by fracture zone beside large fracture. We should find " LiBa type" and " DaGouLi type" gold mine in the district. |
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