Abstract The San Felix - San Ambrosio Oceanic Volcanic Complex (SSOVOC), located in the Southeast Pacific, 940 km offshore northern continental Chile, corresponds to a case of intraplate volcanism in the Nazca Plate. The complex is comprised of San Felix, San Ambrosio and Gonzalez islands, which are mainly composed of alkaline lavas and hyaloclastic sequences. San Ambrosio Island (2.86–2.93 Ma) would be made up mainly, in its subaerial section, of two eruptive shield-type events called Carpa Group and Fardelas Group, the latter event being slightly more alkaline than the Carpa Group. The Gonzalez Islet (1 Ma?) is made up of a Hyaloclastic Unit, submarine and subaerial basanitic lava flows and the Punta Bari Group, the latter described previously on San Felix Island. The Hyaloclastic Unit and basanitic lava flows have textures associated with an underwater deposition environment and a subsequent transition to a subaerial environment. Geochemical data indicate an increase in alkalinity between San Ambrosio Island and Gonzalez Islet and different degrees of partial melting based on Th/Nd vs Th and Rb/Nd vs Rb data and enrichment in incompatible trace elements suggest a decrease in partial melting between the generating event of San Ambrosio Island and Gonzalez Islet. The isotopic mixing model of Sr and Nd indicates that this volcanic complex represents a mixing of 35%–45% between DM and EM-I members, although from the San Ambrosio Island to Gonzalez-San Felix Islands there is an independent trend between both islands towards EM-I, which suggests a cortical contamination of the same volcanic edifice of which the three islands of the complex are part.

中文翻译：

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智利东南太平洋圣安布罗西奥岛和冈萨雷斯岛火山单元的重新解释：使用新的结构和地球化学数据

摘要 圣菲利克斯-圣安布罗西奥海洋火山复合体（SSOVOC）位于智利北部大陆近海 940 公里的东南太平洋，对应于纳斯卡板块的板内火山作用。该综合体由圣菲利克斯岛、圣安布罗休岛和冈萨雷斯岛组成，主要由碱性熔岩和透明碎屑层序组成。San Ambrosio Island (2.86–2.93 Ma) 在其地下部分将主要由两个称为 Carpa Group 和 Fardelas Group 的喷发盾型事件组成，后者事件比 Carpa Group 碱性略强。冈萨雷斯岛 (1 Ma?) 由透明碎屑单元、海底和地下玄武岩熔岩流和 Punta Bari Group 组成，后者先前在圣菲利克斯岛描述过。透明碎屑单元和玄武质熔岩流具有与水下沉积环境和随后向地下环境过渡相关的纹理。地球化学数据表明圣安布罗休岛和冈萨雷斯岛之间的碱度增加，并且基于 Th/Nd 与 Th 和 Rb/Nd 与 Rb 数据的不同程度的部分熔化以及不相容微量元素的富集表明生成事件之间部分熔化的减少圣安布罗休岛和冈萨雷斯岛。Sr 和 Nd 的同位素混合模型表明，该火山复合体代表 DM 和 EM-I 成员之间 35%–45% 的混合，尽管从 San Ambrosio 岛到 Gonzalez-San Felix 岛之间存在独立的趋势对 EM-I，