ROW: Geochemical Evolution of Alkaline and Peralkaline Magmatism Associated with Oceanic Rift Failure: Revillagigedo Islands, Mexico

东太平洋的索科罗岛和圣本尼迪克托岛非常引人注目，因为它们位于一个最近被遗弃的扩散中心的轴线上（-3.15 Ma前），但仍然有火山活动。此外，索科罗岛的独特之处在于它是太平洋上唯一一个以盐为主的过碱性海洋岛屿。这项研究将记录索科罗和圣本尼迪克托群岛在山脊断裂背景下的地质和地球化学历史。主要元素和微量元素、40Ar-39Ar年代学以及整个岩石、玻璃和斑晶的Sr、Nd、Pb和Th同位素分析将在该地区海底地形高地进行。研究的目的是：1)描述Socorro和San Benedicto群岛的地球化学演化特征；2)限制了Socorro岩浆储层的深度和可能的体积；3)在解释Socorro岛喷发历史和盐碱型过碱性岩浆的成因方面，证明了成分分层与基性补给的相对重要性；4)建立近代区域岩浆活动来源与洋中扩张中心废弃岩浆活动来源的时间和地球化学关系。

Socorro and San Benedicto Islands in the Eastern Pacific Ocean are remarkable because they are located on the axis of a recently abandoned spreading center (-3.15 Ma ago) and yet are still volcanically active. Moreover, Socorro Island is unique in being the only predominantly salic peralkaline oceanic island in the Pacific Ocean. This research will document the geologic and geochemical histories of Socorro and San Benedicto Islands in the context of ridge failure. Major and trace element, 40Ar-39Ar geochronology, and Sr, Nd, Pb, and Th isotopic analyses of whole rocks, glasses and phenocrysts will be conducted on samples from submarine topographic highs in the region. The purpose of the research is to: 1) characterize the geochemical evolution of Socorro and San Benedicto Islands; 2) constrain the depth and possibly volume of the magma reservoir beneath Socorro; 3) document the relative importance of compositional stratifications versus mafic recharge in explaining both the eruptive history of Socorro Island and the origin of salic peralkaline magmas; and 4) 4) establish the temporal and geochemical relationship between sources of recent regional magmatism and those of the abandoned mid-ocean spreading center.