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

对大洋中脊、库克-南方岛链以及特里斯坦·达库尼亚岛和高夫玄武岩的同位素和微量元素研究

• 批准号: 5441348
• 负责人: Professor Dr. Andreas Stracke, Ph.D.
• 金额: --
• 依托单位: Institut für Mineralogie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2004
• 资助国家: 德国
• 起止时间: 2003-12-31 至 2006-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5441348?language=en
• 关键词: Isotopen; und; Spurenelementuntersuchungen; Basalten; von

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.

建议对库克-奥斯特拉尔岛链、圣赫勒拿、特里斯坦-达库尼亚和高夫以及大洋中脊玄武岩进行详细的地球化学研究（Sr、Nd、Pb和Hf同位素以及主要和微量元素测量）。Cook-Austral链玄武岩覆盖了洋岛玄武岩（OIB）同位素阵列的三分之二，范围从HIMU类（具有高Pb同位素比的玄武岩的缩写）到EM类玄武岩（具有高Sr，低Nd和Pb同位素比的玄武岩的缩写）。HIMU类玄武岩分为两种不同的类型。一个是同位素类似于圣赫勒拿玄武岩，另一个是类似于富集MORB。对CookAustral玄武岩和MORB的详细调查将显示这两个签名是否具有共同的遗传起源。此外，还将研究循环沉积物在库克-奥斯特拉尔、高夫和特里斯坦-达库尼亚库尼亚地幔源区中的潜在作用。只有将常量和微量元素与同位素数据结合起来才能完整地表征地幔物质的来源，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。这些信息对于解释全球地幔结构和演化模型的地球化学数据至关重要。