| the paper studies some geological and geochemical characteristics systematically of the Thallium (Mercury) deposit, Proposes the metallogenic model of Lanmuchang Type Thallium(Mercury)Deposit and Summarizes some clue for prospecting and assessment with multidisciplinary theories and research methods of mineral deposits geology,mineralogy,petrology,mineralgrapy,geochemistry,stratagraphy and structural geology.Southwestern GuiZhou Province is a metallogenic belt of T1-Au-Hg-Sb-As. Permian and Triassic Yelang formation are major ore-bearing strata. Two element's contents are distinguished with Kolmgrov-smirnov test in ore-bearing strata. One is resulted from normal sedimentary process(A),another(M)is caused by normal sedimentary process, ore-forming process and other processes. The results show that contents of Hg, Sb, As, Au, and T1(M/A>5)are enriched or strongly enriched in the ore-bearing strata of the district, but contents of Pb, Zn are normal or slightly enriched (M/A<2), as the above studied, it shows that Emeishen basalt formation, Longtan formation,Changxing-Dalong formation and Yelang formation which are not only major ore-bearing strata but also source bed.Data analysis of trace elements show that there are some basic and felsic volcanic ash which contain K-bearing minerals such as K-feldspar and mica.Tl and K are closely related to magmatism because of the geochemical chareacteristic of thallium, it is proposed that thallium is derived from the felsic volcanic material. Finally, according to the data of fluid inclusion, REE, isotope and geology condition, the metallogenic model of Lanmuchang Type Thallium(Mercury)Deposit is proposed, the basic and felsic volcanic material are altered to be illite with releasing a small amount of T1,Ba,and SiO2 after alteration caused by hydrothermal. T1,Ba is released with illite altered into kaolinite, the ores were precipitated in the suitable condition accompanied by kaolinization and baritization.Finally, some prospecting evidences and assessment clue are proposed according to the regional structural setting, ore-bearing feature of strata, sedimentary environment, host rock alteration, and mineral assemblage. |
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