| 南京栖霞山铅锌矿床成因探讨 |
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| 引用本文：.1985.On the genesis of the Qixiashan lead-zine ore deposit of Nanjing[J].Mineral Deposits,4(1):11~21 |
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| On the genesis of the Qixiashan lead-zine ore deposit of Nanjing |
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| Abstract:The Qixiashan lead-zine polymetallic ore deposit is apparently controlled by strata, lithology and structure and has complicated mineral and chemical compositions and relatively simple major minerals as well as very as very weak wall rock alterations such as silicification, carbonitization and baritization characterized by medium-low metallogenic temperatures. The sulfur isotope composition of the sulfide ore are distributed scatteringly(δS34 values being -27.4—+14.1%), showing a tower-type distribution pattern along”0” value on the isotope frequency histogram. The lead in the ore belongs to normal-type one, having model ages(φvalues) of 568-707 m.y. and initial lead time of pre-cambrian. The oxygen and carbon isotope compositions suggest that the ore-forming hydrothermal fluids originated mainly from the strata and the meteoritc water. The circulation of the infiltrated thermal brine and the “fracturing-karstification” must have played and important role in metallogenic process. No intrusive body has been observed at the surface of the mining ares, but a medium-acid magmatic intrusion might exist at depth in west of the mining area, which undoubtedly provided thermal energy and part of ore-forming materials for the formation of the ore deposit. The mineralization process underwent three stages, i. e., Caledonian-Hercynian sedimentary stage, Indo-Sinian thermal brine circulation and paleokarstification stage and middle-late Yenshanian metallogenic stage. Studies show that the metallogenic elements were derived predominantly from pre-Cambrian basement rock and partly from ore-lacalizing beds and magma. These ore-forming materials were first released from the basement and the strata as a result of deep circulation of thermal brine and paleokarstification, and then formed mineralization solution, which migrated along faults and eventually precipitated in favorable structures and carbonate beds. It is therefore conceivable that the metallogenic activities occurred later than the formation of ore-localizing strata and the ore deposit was finally produced in the middle-late Yenshanian period. Consequently the ore deposit can be considered to be of crust-derived dpigenetic stratabound type. |
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