Stratigraphically Controlled Geochemical Studies of South Atlantic Ocean Island Volcanism: Ascension Island

该项目将研究受地层控制的阿森松岛火山的微量元素和同位素(放射性和稳定性)特征，以确定不相容的微量元素和同位素比率的变化幅度，从而确定洋岛玄武岩(OIB)来源成分和OIB来源之间的混合关系。阿森松岛上大量的火山碎屑岩尚未确定其特征；PIS将对火山碎屑岩的火山学、岩石学和地球化学与熔岩流和该岛的整体岩浆演化进行详细研究。由于阿森松火山岩的微量元素和同位素特征似乎是大多数OIB的典型特征，因此全面评估这种OIB类型的岩石成因和成因是很重要的。

This project will examine the trace element and isotopic (radiogenic and stable) characteristics of stratigraphically- controlled Ascension Island volcanics to establish the magnitude of variations in incompatible trace-element and isotopic ratios, in order to determine mixing relationships between ocean island basalt (OIB) source components, and the origin of OIB. The voluminous pyroclastics on Ascension are as yet uncharacterized; the PIs will undertake a detailed study of the volcanology, petrology and geochemistry of the pyroclastics in relation to the lava flows and the overall magmatic evolution of the island. As the trace element and isotopic characteristics of Ascension volcanics appear to be typical of the majority of OIB, it is important to fully assess the petrogenesis and origin of this OIB type.