RUI: Contrasting Differentiation Processes in Oceanic MagmaChambers: Sierra Negra and Alcedo Volcanoes, Galapagos Islands

加拉帕戈斯火山Sierra Negra和Alcedo代表了岩浆多样性的两个极端。Sierra Negra由成分相似的演化拉斑玄武岩组成，而Alcedo则喷发出了拉斑玄武岩和海洋流纹岩的双峰组合。人们认为，这两座火山分化程度的差异与它们岩浆房历史的根本差异有关，但这两座火山如此接近，以至于它们的侧翼重叠。该项目将对阿尔塞多火山进行详细的野外、岩石学和地球化学研究，以便开始阐明这些差异。将特别强调确定这组独特的海洋流纹岩的起源。将确定不同单元的体积、喷发顺序和喷发地点。这些反过来又将为控制海洋岩浆演化的岩石学过程提供限制。最终计划研究Sierra Negra以进行比较，但这样的研究不属于本项目的一部分。

The Galapagos volcanoes Sierra Negra and Alcedo represent two extremes of magmatic diversity. Sierra Negra is made up of compositionally similar, evolved tholeiitic basalts, whereas Alcedo has erupted a remarkable bimodal suite of tholeiitic basalts and oceanic rhyolites. It is believed that the difference in the extents of differentiation of these two volcanoes is related to fundemental differences in their magma chambers' histories, yet the two are so close that their flanks overlap. This project will perform detailed field, petrologic and geochemical studies of Alcedo volcano, in order to begin to elucidate these differences. Particular emphasis will be placed on determining the origin of the unique suite of oceanic rhyolites. Volumes of the different units, their eruptive order, and the locations of eruptions will be determined. These in turn will provide constraints on the petrologic processes that govern the evolution of oceanic magmas. Eventually it is planned to study Sierra Negra for comparison purposes, but such a study is not part of this project.