Evolution of the Galapagos Hotspot

该项目将对加拉帕戈斯熔岩流进行综合的地球化学、同位素和年代学研究，以确定加拉帕戈斯热点的起源，并将其与其他海洋热点（如夏威夷）进行比较。 评估加拉帕戈斯火山时间演变的一个重要障碍是缺乏喷发时间表。 该项目将在很大程度上依赖于相对较新的地表暴露年代测定法（使用宇宙射线产生的核素，如3He和36Cl）来确定熔岩流的年龄。 将新的年龄信息与地球化学数据（即锶、钕、铅和氦的同位素）相结合，将有助于确定加拉帕戈斯火山之间巨大的地球化学差异是否与时间或空间变化有关，这对热点模型至关重要。 研究的一个关键目标是评估Cerro阿苏尔和Fernandina的时间演变，这两座最活跃的火山被认为是西端群岛的中心附近。 该项目还将生成一个从费尔南迪纳到圣克里斯托瓦尔的自西向东的地球化学断面，以评估板块构造范例中的热点模型。 新的野外工作将提供这些结果与平塔和马尔切纳的北方火山的地球化学比较，这些火山目前难以用标准热点模型解释。

KurzEAR-0126097This project will involve a combined geochemical, isotopic, and chronological study of Galapagos lava flows in order to constrain the origin of the Galapagos hotspot and to compare it to other oceanic hotspots, such as Hawaii. An important obstacle to evaluating the temporal evolution of Galapagos volcanoes has been the lack of an eruption time scale. This project will rely heavily on the relatively new dating method of surface exposure dating (using cosmic-ray-produced nuclides such as 3He and 36Cl) to determine lava flow ages. Combining the new age information with the geochemical data (i.e. the isotopes of strontium, neodymium, lead and helium) will help determine if the large geochemical differences between Galapagos volcanoes are related to temporal or spatial variability, which is crucial to hotspot models. One key goal of the research will be to evaluate temporal evolution at Cerro Azul and Fernandina, the two most active volcanoes in the western end archipelago which are thought to be near the center of the present-day hotspot. The project will also generate a west-to-east geochemical transect from Fernandina to San Cristobal to evaluate the hotspot model in the paradigm of plate tectonics. New field work will provide a geochemical comparison of these results to the northern volcanoes on Pinta and Marchena which are presently difficult to explain in standard hotspot models.