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新测得 TAG热液区中 6件海底表层热液沉积物样品的铅同位素组成 ,其变化范围不大 ,具有均一性的特征。在 Pb- Pb图解上 ,热液沉积物的铅同位素数据大多落在 MARB的铅同位素组成范围内 ,与大西洋沉积物和 Fe- Mn结核相比明显具较少的放射成因铅 ,反映其上部洋壳岩石为该区热液沉积物的形成提供了铅。对比研究表明 ,因不同地质 -构造环境中的海底热液区为热液沉积物形成提供物源的情况不同 ,是导致有沉积物覆盖洋中脊中热液沉积物的铅同位素组成与无沉积物覆盖洋中脊不同的主要原因。海底扩张中心的扩张速率与热液沉积物的铅同位素组成有一定的对应关系 ,但其并不是热液沉积物铅同位素组成的唯一控制因素
The newly measured Pb isotopic compositions of six seafloor surface hydrothermal sediment samples in the TAG hydrothermal zone show little variation and homogeneity. On the Pb-Pb plot, most of the Pb isotopic data of hydrothermal sediments fall within the Pb isotope composition of MARB, with significantly less Pb-induced lead than the Atlantic sediments and Fe-Mn nodules, reflecting the upper ocean Shell rocks provide lead for the formation of hydrothermal deposits in the area. Comparative studies have shown that different sources of hydrothermal deposits due to submarine hydrothermal zones in different geological-tectonic settings result in the formation of lead isotopes with and without deposition of overlying mid-ocean ridges in hydrothermal sediments The main reason for covering different mid-ocean ridges. The expansion rate of the submarine expansion center is related to the lead isotopic composition of hydrothermal sediments, but it is not the sole controlling factor of the composition of lead isotopes in hydrothermal sediments