Collaborative research: Dynamics and origins of explosive silicic volcanism at 2300 mbsl on a mid-ocean spreading center

人们对深海环境中的硅质火山喷发知之甚少，因为发现和记录的很少。在陆地上，这些类型的喷发对居住在火山附近和/或任何火山灰云扩散带路径沿线的居民构成重大危险。这项研究分析了2012年蒙特雷海湾水族馆研究所(MBARI)前往加利福尼亚州海湾阿拉康隆起的样品，当时发现了一个独特的硅质(流纹岩、英安岩、安山岩)喷发中心，位于海平面以下2300至2400米。这项研究的目标是填补我们对深海火山爆发事件的理解的一个重大空白。工作包括收集喷发中心挥发和脱气历史的综合地球化学、岩石学和火山学数据集。它将涉及合并从该地区高分辨率(1米)水深图获得的地形/地物信息，以及对6个火山碎屑勺袋和24个含有浮石和流体硅物质样品的推芯进行分析。数据将被用来确定岩浆分异和挥发分浓缩的机制，以及火山碎屑的运移过程、火山碎屑的分散程度和破碎机制。它还将通过测量挥发分(水、二氧化碳、S等)来确定岩浆挥发分在多大程度上影响深海爆炸喷发中的岩浆粘度和喷发方式。喷发杯里的东西。此外，还将进行U-Th、U-Th/He和Ar年龄测定，以确定矿床是否代表一次以上的喷发，如果有一次以上，则确定它们发生的时间。收集的熔岩和玻璃的稳定同位素(O和H)和放射性同位素(锶、钕、铅、氢)都将被分析，以研究潜在的大陆和海洋地壳同化在喷发起源中的影响(S)。这项研究的更广泛的影响是强大和多方面的。这些活动包括为教育工作者创建一个网站和研究区域及其火山和火山沉积物的虚拟现实展示，并在YouTube和蒙特雷海湾水族馆研究所开放日上分发这一视频。此外，还与墨西哥和澳大利亚的科学家开展了重要的国际合作；通过开发加州大学圣克鲁斯分校的新的地球化学分析程序和能力，将增加科学基础设施。其他影响是，该项目支持两个早期职业绩效指标，其中一个在EPSCoR州(罗德岛)的一家机构。

Very little is known about explosive silicic volcanic eruptions in deep sea environments because so few have been discovered and documented. On land these types of eruptions pose significant hazards for populations living near the volcano and/or along the path of any ash cloud dispersal zone. This research analyzes samples from a 2012 Monterrey Bay Aquarium Research Institute (MBARI) cruise to the Alarcon Rise in the Gulf of California that discovered a unique silicic (rhyolite, dacitic, andesitic) eruption center lying 2,300 to 2,400 meters below the sea surface. Goals of the research are to fill a major gap in our understanding of deep marine explosive volcanic events. Work includes collection of a comprehensive geochemical, petrological, and volcanological dataset of the volatile and degassing history of the eruptive center. It will involve merging topographic/feature information obtained from high resolution (1 meter) bathymetric maps of the area and analyses of 6 volcaniclastic scoop bags and 24 push cores that contain samples of pumice and fluidal silicic material. Data will be used to determine the mechanism of magmatic differentiation and volatile enrichment, as well as volcaniclastic transport processes, pyroclast dispersal extent, and fragmentation mechanisms. It will also determine how much magmatic volatiles influence magma viscosity and eruption style in deep sea explosive eruptions by measuring the volatile (H2O, CO2, S, etc.) contents in the eruptive glasses. Additionally, U-Th and U-Th/He and Ar age dating will take place to determine if the deposits represent more than one eruption and, if there is more than one, when they took place. Both stable isotopes (O and H) and radiogenic isotopes (Sr, Nd, Pb, Hf) of the collected lavas and glasses will be analyzed to examine impacts of potential continental and oceanic crustal assimilation in the origination of the eruption(s). Broader impacts of the research are strong and multifaceted. They include the creation of a website and virtual reality displays of the study area and its volcano and volcanic deposits for educators and the distribution of this visual over YouTube and at the Monterrey Bay Aquarium Research Institute Open House. There is also significant international collaboration with scientists from Mexico and Australia; and there will be an increase in the infrastructure for science by developing new geochemical analytical procedures and capabilities at the University of California, Santa Cruz. Additional impacts are that the project supports two early career PIs, one of whom is at an institution in an EPSCoR state (Rhode Island).