EAPSI: Understanding Crystal Cluster Origins in Magmas Erupted from Toba Caldera, Earth's Youngest Supervolcano

超级火山爆发，地球上最猛烈的火山爆发，是由含有大量富含硅的岩浆的岩浆库提供的。在这些岩浆中形成的晶体以及在喷发产物中发现的晶体包含了导致这种毁灭性喷发过程的重要信息。该项目将研究74000年前爆发的最年轻的多巴凝灰岩（YTT）的硅岩浆储层的储存条件和动力学，然后在印度尼西亚苏门答腊的多巴火山口（Toba Caldera）静静地挤出几个小流纹岩熔岩圆顶。这些多巴岩浆含有不寻常的石英晶体簇，可能记录了它们的宿主岩浆发育的重要证据。石英簇很少在其他破火山口岩浆系统的硅质火山岩中被发现或研究，因此将对多巴石英簇进行研究，以了解它们的起源及其对硅质岩浆演化和喷发潜力的影响。这项研究将在新加坡南洋理工大学进行，由卡罗琳·布韦·德·迈森纽夫博士指导，她是利用晶体尺度数据确定岩浆储存条件和喷发动力学的专家。岩石学和阴极发光成像显示，石英簇化是影响40-60% YTT和熔岩穹窿晶体的重要过程。单个石英单元的晶体学取向将获得集群内部的资料，以确定集群形成的潜在机制，以及它们产生的环境类型。微量元素分析将用于在给定的集群中对每个单元进行化学指纹，以确定单个单元是否在相似的岩浆条件下形成，从而确定可能是在同一时间形成的。研究结果将对多巴岩浆储层的岩石学、流变学演化和动力学提供重要的约束，并有望突出从火山口前到火山口后的岩浆储存条件和喷发潜力的转变。多巴石英簇的特征也将与固化的地下岩浆体的特征进行比较，以提供对火山岩与深部岩体之间联系的见解。该奖项由美国国家科学基金会与新加坡国家研究基金会共同资助。

Supereruptions, the most violent volcanic eruptions on Earth, are fed by magma reservoirs that contain incredibly large volumes of silica-rich magma. Crystals formed within these magmas and found in their eruptive products contain important information on the processes that lead to such devastating eruptions. This project will investigate the storage conditions and dynamics of the silicic magma reservoir that explosively erupted the voluminous Youngest Toba Tuff (YTT) 74,000 years ago and then quiescently extruded several small rhyolite lava domes at Toba Caldera (Sumatra, Indonesia). These Toba magmas contain unusual quartz crystal clusters that likely record important evidence for the development of their host magma. Quartz clusters have seldom been recognized or studied in silicic volcanic rocks from other caldera-forming magma systems, and thus the Toba quartz clusters will be examined to understand their origin and the implications they have for silicic magma evolution and eruption potential. This research will be conducted at Nanyang Technological University in Singapore under the guidance of Dr. Caroline Bouvet de Maisonneuve, an expert on the use of crystal-scale data to determine magma storage conditions and eruption dynamics.Petrography and cathodoluminescence imaging reveal that quartz clustering is an important process affecting 40-60% of YTT and lava dome crystals. Crystallographic orientations of individual quartz ?units? within clusters will be acquired to identify potential mechanisms for cluster formation, as well as the type of environment from which they originated. Trace element analysis will be used to chemically fingerprint each unit in a given cluster to determine whether the individual units formed under similar magma conditions, and thus potentially at the same time. Results will provide important constraints on the petrological and rheological evolution and dynamics of the Toba magma reservoir and are expected to highlight a transition from pre- to post-caldera magma storage conditions and eruption potential. Toba quartz cluster features will also be compared to those reported from solidified subsurface magma bodies to provide insight on the connection between volcanic rocks and their plutonic counterparts. This NSF EAPSI award is funded in collaboration with the National Research Foundation of Singapore.