EAPSI: Understanding Variations in Thermal Histories in Volcanic Centers Over Time and Space

大型的火山中心是地球上最具灾难性的火山爆发的原因，包括大规模的“超级火山”爆发。为了预测超级火山何时可能爆发，重要的是要了解岩浆在爆发前产生和储存的时间尺度。特别是，不清楚岩浆体以大部分固体状态（即，作为低温富含晶体的糊状物），相对于它们在大部分液体中的时间（即，高温）、可喷发状态。该项目将检查新西兰陶波火山区（TVZ）喷发产物的晶体，该火山区是世界上最活跃的火山区。这项工作的目标是双重的：1）确定晶体的存在有多大比例是在岩浆库中的高温下度过的; 2）确定岩浆在火山中心的时间和空间中如何不同地演变。这项研究将与新加坡南洋理工大学的Fidel Costa Rodriguez博士合作进行。Fidel Costa Rodriguez博士是利用扩散剖面确定岩浆温度的专家。为了确定晶体在高温下的存在比例，有必要限制晶体的绝对年龄。一系列TVZ喷发的斜长石晶体年龄将通过测量U系列不平衡年龄来获得，结晶年龄和喷发年龄之间的差异将产生在地下花费的时间。将完成对扩散分布（随温度变化的微量元素分布）的分析，以确定晶体的地下存在有多大比例是在高温下度过的。结果将在一系列喷发之间进行比较，以确定火山中心如何随时间和空间演变，以及不同规模的喷发演变之间存在哪些差异。这个NSF EAPSI奖是与新加坡国家研究基金会合作资助的。

Large silicic volcanic centers are responsible for the most catastrophic volcanic eruptions on earth, including massive 'supervolcanic' eruptions. In order to potentially anticipate when a supervolcano is likely to erupt, it is important to understand the timescales over which magma is generated and stored prior to eruption. In particular, it is not clear for how long magmatic bodies reside in the subsurface in a mostly-solid state (i.e., as low-temperature crystal-rich mushes), relative to how long they spend in a mostly-liquid (i.e., high-temperature), eruptible state. This project will examine crystals from eruptive products from the Taupo Volcanic Zone (TVZ) in New Zealand, the most active volcanic zone in the world. The goals of this work are twofold: 1) to determine what proportion of a crystal's existence was spent at high temperatures within a magma reservoir; 2) to determine how magma evolves differently over both time and space within a volcanic center. This research will be conducted in collaboration with Dr. Fidel Costa Rodriguez, an expert on the use of diffusion profiles to determine magmatic temperatures, at Nanyang Technological University in Singapore.In order to determine what proportion of a crystal's existence was spent at high temperatures, it is necessary to constrain the absolute age of the crystal. Plagioclase crystal ages from a series of TVZ eruptions will be acquired by measuring U-series disequilibrium ages, and the difference between the crystallization age and the eruption age will yield the amount of time spent in the subsurface. Analyses of diffusion profiles (temperature-dependent trace element distributions) will be completed in order to determine what proportion of the crystal's subsurface existence was spent at high temperatures. Results will be compared between a series of eruptions to determine not only how volcanic centers evolve over time and space, but also what differences exist between the evolutions of eruptions of different magnitudes. This NSF EAPSI award is funded in collaboration with the National Research Foundation of Singapore.