Northwest Guizhou Pb-zn Deposits Rules And Prospecting

The lead and zinc metallogenic zone in Chuan-Dian-Qian.district lies at the southwest edge of Yangzi platform and in the zone which is surrounded by three deep fracture zones named by Xiaojiang, Shi zhong-MiLe, YaDou-ZiYun. The metallogenic zone is one of sixteen important metallogenic provinces during "10.5 Year Plan "and" 11.5 Year Plan "in our country. The metallogenic zone of lead and zinc ore in the northwest of Qian lies at the east of the metallogenic zone of lead and zinc ore in Chuan-Dian-Qian district. It is one of the important lead and zinc mines in Guizhou province. This place has the potential of seeking middle-scale or large-scale lead and zinc deposit, because physics and chemistry prospection abnormity appears the group-shaped and belt-shaped distribution and the metallogenic geological condition is superior.Regional structure spreading in the lead and zinc metallogenic zone in the northwest of Qian and lead-zinc mineralization in this place takes on obvious belt-shaped distributing character. The author divides four structure belts and three metallogenic sub-belts based on the structure and mineralization feature of the metallogenic zone. This dissertation firstly sets forth in the detail the evolvement character of regional structure, the geologic character and metallogenic character of every structure belt and metallogenic sub-belt, the relation between physics and chemistry prospection abnormity and lead and zinc metallogeny.The research on the metallogenic factor and controlling factors for lead-zinc deposits shows that the metallogenic factors of lead and zinc in this place include stratum(Sl-2hj-P2m), lithology(carbonate rock), structure (NW overthrust fault mainly+NE cross fracture+fracture belt and anticline plunging end), eruptive (beside diabase, under basalt stratum), lithofacies (overlap up argillaceous and under carbonate lithofacies), sediment environment (inboard submarine carinate uplift.closed or half-closed reducing lagoon deposit entironment) etc. Fracture is the most important controlling metallogeny factor and control factors for ore deposit by lithology precede over horizon. The main ore-containning horizon in this place gradually runs up from the west to the east, from south to north in the spatial distribution and becomes new step by step in the time evolution. These phenomena shows that denudation degree is low in the northwest of Qian, horizon ore-containning keep in good condition and the depth portion prospecting has the very good prospect.Graduation controlling ore by the structure is obvious. Fault-basin edge controls ore belt extentâ†'compacted folds and longitudinal fault growing from the core of compacted fold controls mineral deposit extentâ†'the intersecting position of trunk fault and sub-fault and arch lean end in mineral deposit control mineral deposit and orebody attitude. REgional big fracture +sub-fracture+extrusion crush belt in stratum are good controlling ore system by structure and collecting, storage ore system. This dissertation firstly research all-sided ore-controlling mechanism by structures.The characteristics of Pb,S,C,O isotopes, REE and regional geochemistry background show the metallogenic substance has many sources and metallogenic action has many stages. Metallogenic element Pb,Zn,Ag mainly came from underlying old stratum. Their cause of formation have been related with sub cambrian system clasolite, presinian basement pyroclastic rock and E Mei Mountain basalt. S,O in metallogenic liquid came from sea phase sulfate, C came from sea phase carbonate, water mainly came from deep stratum metamorphic water and partly from precipitation.The character of ore inclusion reveals that the metallogenic fluid is a Ca-Na-Cl(SO4) mineralization liquid which has low temperature, middle-high salinity, reducing condition, weakly-alkali—weakly-acidic, and high mineralised quality.Study shows that the genetic type of the ore deposits is similar to Mississppi valley type (MVT) lead and zinc deposits, but the vein-shaped character in shallow site is obvious, which reveals the ore deposits is not a typed MVT one. Combining the character of the regional structural evolvement and the metallogenic geological quality, the author sets up the MVT model of metallogeny of the local district and the synthetical model of seeking mine, whose mainly controlled factor is fracture structure.Synthesizing the minerals potential, metallogenic prognosis and recent years results for all typical mineral deposites (fields) in the metallogenic provinces the author believes that the North-West of Qian in deep parts have huge potential to mineral deposits, and have middle-large deposits'conditions. The important mineral-finding target zones are Hezhangmaomaochang-Zhaizichang ore field deep parts; Yadu-Mangdong fracture zone's Yadu, Xiaojiwan ore field deep parts and periphery; Shuicheng-Qing mountain ore field deep parts and periphery, Shanshulin ore field deep parts; Weining-Yinchangpo ore field deep parts. Superficial places mainly seek to steep-nervation fracture type, deep parts (exceed 500meters) mainly find out Stratoid-Interstratification fracture zones, which all indicate this zone seek to mineral's directions and main research types in future.