Isotopen- und Spurenelementuntersuchungen an Basalten von Mittelozeanischen Rücken, der Cook-Austral Inselkette, sowie von Tristan da Cunha und Gough

对Cook-Austral链玄武岩、St. Helena、Tristan da Cunha和Gough玄武岩以及洋中脊玄武岩（MORB）进行了详细的地球化学研究（Sr、Nd、Pb、Hf同位素和主微量元素测量）。Cook-Austral链玄武岩覆盖了海洋岛玄武岩（OIB）同位素阵列的2 / 3，从himu型玄武岩（高Pb同位素比玄武岩的缩写）到em型玄武岩（高Sr、低Nd和Pb同位素比玄武岩的缩写）。类玄武岩分为两种不同的类型。一个与圣赫勒拿岛玄武岩同位素相似，另一个与富集的MORB岩同位素相似。对CookAustral玄武岩和MORB的详细调查将表明这两个特征是否具有共同的成因。此外，还将研究再循环沉积在Cook-Austral玄武岩、Gough玄武岩和Tristan da Cunha玄武岩地幔源中的潜在作用。只有将主微量元素与同位素数据结合起来，才能完整地表征地幔的来源，而且还可以提供有关熔融原因、熔体提取机制和非均质地幔物质规模的信息。这些信息对于用全球地幔结构和演化模型解释地球化学数据是必不可少的。

A detailed geochemical study of basalts from the Cook-Austral chain, St. Helena, Tristan da Cunha and Gough as well as mid ocean ridge basalts (MORB) is proposed (Sr, Nd, Pb, and Hf isotope and major and trace element measurements). Basalts from the Cook-Austral chain cover two thirds of the ocean island basalt (OIB) isotopic array and range from HIMU-like (acronym for basalts with high Pb isotope ratios) to EM-like basalts (acronym for basalts with high Sr, low Nd and Pb isotope ratios). HIMU-like basalts group into two different types. One is isotopically similar to St. Helena basalts, the other is similar to enriched MORB. A detailed investigation of CookAustral basalts and MORB will show whether these two signatures have a common genetic origin. In addition, the potential role of recycled sediment in the mantle source of the Cook-Austral, Gough and Tristan da Cunha basalts will be investigated. Only combining major and trace element with isotopic data allows complete characterization of mantle sources, but can also provide information about the cause of melting, melt extraction mechanisms and the scale of the heterogeneous mantle materials. This information is essential for interpreting geochemical data in terms of global mantle structure and evolution models.