【摘要】 贵州新元古代陡山沱期瓮福磷矿下矿层条纹-条带状磷块岩的磷条带、泥岩条带、上矿层磷块岩的磷质、白云质胶结物有各自不同的铅同位素组成特点。在Zartman铅构造模式图解中,下矿层磷条带和泥质磷块岩条带位于地幔铅、造山带铅和上地壳演化线之间,并呈很好的线性关系。上矿层磷块岩的白云质胶结物远离所有类型铅的演化线。下矿层的泥岩条带位于幔源铅和上地壳铅演化线之间,但与磷质不同,更偏向于白云质胶结物的分布区。在朱炳泉等(1998)的Δγ-Δβ铅来源分类图上,上矿层和下矿层所有磷质样品分布于地幔铅、上地壳与地幔混合俯冲带碎屑沉积作用铅和海底热水作用铅区。上矿层磷块岩的白云质胶结物分布于上地壳和地幔混合俯冲带岩浆作用铅、化学沉积型和海底热水作用型铅区。泥岩条带分布于地幔源和海底热水作用型铅区。因此,瓮福磷矿磷质样品的铅主要具地幔铅、上地壳铅和热水沉积作用的混合来源,以地幔为主。上矿层白云质胶结物铅同位素具有海源和海底热水作用的混合来源。下矿层泥岩条带铅同位素具地幔、上地壳和海源铅的混合特点。陡山沱期大规模磷质成矿的初始物质主要来源于地幔,预示着磷质的超常成矿与磷质生物的爆发可能与地幔体制的变化有某种成因联系。更多还原

【Abstract】 There are different lead isotope characteristics between phosphorite bands and mudstone bands in the lower ore beds, and phosphorus minerals and dolomite cements of phosphorites in the upper ore beds. The values of 206Pb/204Pb with 17.884～18.239, 207Pb/204Pb with 15.479～15.546 and 208Pb/204Pb with 37.356～38.030 in phosphorite bands are different from the values of 206Pb/204Pb with 17.958～19.005, 207Pb/204Pb with 15.521～15.677 and 208Pb/204Pb with 37.693～38.217 in mudstone bands at lower ore beds; the values of 206Pb/204Pb with 17.772～18.193, 207Pb/204Pb with 15.427～15.762 and 208Pb/204Pb with 37.743～38.521 in phosphorus minerals are different from values of 206Pb/204Pb with 19.344～21.877, 207Pb/204Pb with 15.632～15.793 and 208Pb/204Pb with 37.613～38.177 in dolomite cements of phosphorites at upper ore beds. Phosphorus samples of the upper and the lower phosphorite bands are projected between the extended lines of mantle, orogenic belt and upper crust showing a line in the lead isotopic genetic model by Zartman and Doe (1981). Dolomite cement samples of the upper beds are not located near any extended lines of lead isotopic genetic model. The samples of mudstone bands of the lower beds are located between the extended lines of mantle and upper crust, but they are different with phosphorus samples and preferably located closely to the field of dolomite cement samples. In Δγ Δβ lead isotopic genetic diagram by Zhu Bing quan (1998), all phosphorus samples of the upper and the lower beds are located in the field of mantle, subduction mixed by upper crust and mantle, and hydrothermal sedimentation. The samples of dolomite cements are located in the field of subduction mixed by upper crust and mantle, chemical sedimentation, and hydrothermal sedimentation. The samples of mudstone bands are located in the field of mantle and hydrothermal sedimentation. Therefore, the lead source of phosphate minerals is a mixture of mantle, upper crust and hydrothermal sedimentation and with mantle being the main source. The dolomite cements have multiple sources of ocean and hydrothermal sedimentation. The mudstone bands of the lower beds are derived from a mixture of mantle, upper crust and ocean. The lead sources majored in mantle can provide a new way for studying the formation of super large phosphate deposits and generation of Wengan fauna of Neoproterozoic.更多还原