Abstract:Rock samples were collected at intervals of four meters along 26 section lines in this region, totaling 1452, and subsequent semiquantitative spectral analysis of these samples was performed by a special worker with a special apparatus in the same season. The data acquired was tested by chemical analysis and proved to be unquestionably satisfactory. The Fe, Mn, especially Pb, Zn contents of samples from these section lines, combined with some other data concerned, suggest that middle Devonian Qiziqiao Zu seems likely a major source bed of Pb-Zn deposit. Following are some convincing facts: 1. Of the total 258 Pb-Zn occurrences in this region, one-third are concentrated in Qiziqiao Zu; lots of these occurrences, especially the mineralization sites, are distributed in clusters along the strata. 2. The Pb-Zn contents of Qiziqiao Zu are higher than those of any other sedimentary strata in this region. 3. Distinct geochemical differentiation of Pb and Zn is observed in this region, and areas possessing high or high to medium Pb-Zn abundances seem to spread along basement faults, occurring either at the margin of the platform-basin facies or in lagoon dolomite facies and bioherm bank. One may conclude, therefore, that the existing distribution pattern took shape initially during the Qiziqiao Zu stage. 4. Intense geochemical differentiation has also occurred in high Pb-Zn areas. All the known economic deposits unexceptionally have lower Pb-Zn sections some distance away from the ore bodies and high Pb-Zn sections in relatively distant neighboring areas. This phenomenon, believed to be the result of mineralization processes, serves to be a basis for separating stable zones, "bringing in" zones and "taking out zones of the elements. 5. The model ages calculated from lead isotopes suggest that sedimentary-transformed deposits probably derived their Pb and Zn predominantly from ore source bed and that magmatic-hydrothermal Pb-Zn deposits occurring in carbonate rocks of Qiziqiao Zu and Carboniferous strata should owe a considerable portion of their ore materials to Qiziqiao Zu itself. These facts have led the authors to believe, that the distribution characteristics of Pb and Zn contain information for mineral exploration: the intense Pb and Zn differentiation zones within a high Pb-Zn region are favorable areas in search for Pb-Zn deposits.
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童潜明, 王世明.1984.湖南省南部泥盆系中统棋梓桥组Pb.Zn.Fe.Mn含量特征[J].矿床地质,3(3):27~37.1984.A Study On Pb, Zn, Fe And Mn Contents Of Middle Devonian Qiziqiao Zu In Southern Hunan[J].Mineral Deposits3(3):27~37
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