Collaborative Research: The Leading Edge of the Galapagos Hotspot, A New Window into the Mantle

建议的项目是对加拉帕戈斯群岛西端进行综合海洋实地调查和实验室调查，重点是研究费尔南迪纳火山和塞罗阿祖尔火山海底西侧的熔岩，这些熔岩是在用摄像拖曳和多波束和侧扫声纳绘制地图后形成的。目标是对加拉帕戈斯羽流前沿的火山产物进行定义，然后取样，并进行相关的广泛的地球化学和岩石学研究，这将有助于确定加拉帕戈斯羽流的性质。这些样品将被用来测试前沿地柱火山作用产生的岩浆化学是否确实最好地反映了地幔来源的化学，高3He/4He是否确实反映了未脱气的深部地幔来源，并还将测试加拉帕戈斯独特的马蹄形地球化学变化模式是由于地幔分带作用还是与其他地质过程有关。野外测绘将确定费尔南迪纳以西是否存在一座新的海底火山，它代表了实际的羽流前沿(如夏威夷羽流火山活动中的Loihi所代表的)，正如地震数据所表明的那样。这项位于弱羽流前沿的工作将补充在强羽流夏威夷所做的类似研究，以测试羽流火山作用和起源的模型。

Recommended project is for an integrated marine field and laboratory investigation of the western end of the Galapagos archipelago, with a focus on studying lavas from the submarine western flanks of Fernandina and Cerro Azul volcanoes after mapping them with camera tows and multibeam and side scan sonar. The goal is to define and then sample volcanic products from the leading edge of Galapagos plume, with associated, extensive geochemical and petrological studies that will help define the nature of the Galapagos plume. These samples will be used to test whether magma chemistry from leading-edge plume volcanism indeed best reflects the chemistry of the plume mantle source, whether high 3He/4He does indeed reflect undegassed, deep mantle sources, and also to test whether the unique horseshoe-shaped pattern of Galapagos geochemical variation is due to mantle zonation or is instead related to other geologic processes. The field mapping will determine whether there is a new submarine volcano westward of Fernandina that represents the actual plume leading edge (such as represented by Loihi in the Hawaiian plume volcanism), as suggested by seismic data. This work, on the leading edge of a weak plume, will complement similar studies done at Hawaii, a strong plume, in testing models of plume volcanism and origin.***