EAR-PF: Timescales and processes of magmatic resurgence at Toba caldera

EAR-PF：多巴火山口岩浆复苏的时间尺度和过程

• 批准号: 2204432
• 负责人: Alejandro Cisneros
• 金额: $ 18万
• 依托单位: Cisneros, Alejandro Omar
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2204432&HistoricalAwards=false
• 关键词: EAR; PF; Timescales; processes; magmatic

Volcanoes like Toba and Yellowstone calderas are the sites of the greatest natural catastrophes produced by the Earth: supereruptions. It is no surprise then that significant effort has been put into understanding the nature of these eruptions, their hazards, and the risk they pose to society. However, whereas the build-up to supereruption is now well understood, what happens after a supereruption, the recovery period known as resurgence, is still poorly understood. This is important because all active supervolcanoes on Earth are in this state and still pose a significant hazard. This project seeks to fill this knowledge gap and improve our ability to assess future hazards and risks at supervolcanoes by studying the events after the largest supereruption in the last 2 million years: the Youngest Toba Tuff (YTT; ca. 74,000 years BP) from the Toba Caldera in Indonesia. As an NSF EAR Postdoctoral Fellow, Dr. Cisneros de León will integrate time, chemistry, and temperature information recorded in microscopic crystals erupted at Toba to build a history of the physical and chemical conditions in the magma during recovery after the supereruption. This approach will also reveal the history of eruptions since the supereruption, and allow estimation of the volume of eruptible magma present today beneath the Toba supervolcano enabling better assessment of future risk. The goal of this proposal is to use Toba caldera as a natural laboratory to resolve time and spatial scales of the magmatic processes governing post-caldera resurgence at supervolcanoes. This will be achieved by integrating petrochronology, thermochronology, diffusion, and thermochemical modeling using zircon, allanite, monazite, apatite, sanidine, and quartz to decipher the complementary records of these crystal phases as they pertain to the post-caldera plumbing system and its compositional evolution over decadal to millennial timescales. The specific aims are to 1) develop an integrated petrogenetic approach for investigating pre-eruptive silicic magma reservoirs at all scales based on time, temperature, and chemistry recorded in multiple accessory and major mineral phases; 2) use this information to infer the physicochemical state of pre-eruptive magma storage; and 3) determine the rates at which magmatic processes promote post-caldera eruptions. To accomplish these goals, this study will apply noble-gas 40Ar/39Ar and (U-Th)/He thermochronology to exploit differing closure temperatures of Ar- in sanidine and He- in zircon, monazite, and apatite to resolve eruption ages, storage conditions, and extrusion rates of effusive volcanism from selected post-caldera eruptions. In addition, high-spatial-resolution secondary ion mass spectrometry (SIMS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) will be employed on accessory mineral phases and quartz to determine absolute and relative timescales, respectively, paired to elemental and isotopic compositions. Finally, data from various crystal-scale records will be integrated into thermochemical models to evaluate the current state of the magma system at Toba and the driving forces for resurgent uplift. Thus, constraining the timescales, conditions, and extent over which magmatic processes are occurring in resurgent reservoirs will make a fundamental contribution to eruption forecasting, especially when geophysical approaches are challenged to characterize melt-containing reservoirs at high resolution.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

多巴火山和黄石火山口等火山是地球产生的最大自然灾难：超级喷发的发生地。毫不奇怪，人们已经投入了大量的精力来了解这些火山爆发的性质，它们的危害以及它们对社会构成的风险。然而，尽管超级爆发的积累现在已经很好地理解了，但超级爆发后会发生什么，即所谓的复苏期，仍然知之甚少。这很重要，因为地球上所有活跃的超级火山都处于这种状态，仍然构成重大危险。该项目旨在填补这一知识空白，并通过研究过去200万年来最大的超级火山爆发后的事件来提高我们评估超级火山未来危害和风险的能力：最年轻的多巴凝灰岩（YTT;约。距今74，000年）。作为NSF的博士后研究员，西斯内罗斯德莱昂博士将整合多巴火山喷发的微观晶体中记录的时间、化学和温度信息，以建立超级喷发后岩浆恢复期间的物理和化学条件的历史。这种方法还将揭示超级火山爆发以来的喷发历史，并可以估计多巴超级火山下目前可喷发岩浆的体积，从而更好地评估未来的风险。该提案的目标是利用多巴火山口作为一个自然实验室，以解决时间和空间尺度的岩浆过程管理后火山口复苏的超级火山。这将通过整合岩石年代学，热年代学，扩散和热化学建模，使用锆石，褐帘石，独居石，磷灰石，透长石，石英来破译这些晶体相的互补记录，因为它们属于后破火山口管道系统及其组成演变在十年到千年的时间尺度。具体目标是：1）根据多个辅助矿物和主要矿物相记录的时间、温度和化学成分，开发一种综合的岩石成因方法，用于调查所有尺度的火山喷发前岩浆储层; 2）使用这些信息来推断火山喷发前岩浆储存的物理化学状态; 3）确定岩浆过程促进火山口后喷发的速率。为了实现这些目标，本研究将应用贵气40 Ar/39 Ar和（U-Th）/He热年代学，利用不同的封闭温度的Ar-透长石和He-锆石，独居石，磷灰石，解决喷发年龄，存储条件，和挤出率的喷出火山作用从选定的后破火山口喷发。此外，高空间分辨率二次离子质谱法（西姆斯）和激光烧蚀感应耦合等离子体质谱法（LA-ICP-MS）将用于辅助矿物相和石英，以分别确定与元素和同位素组成配对的绝对和相对时间尺度。最后，将把各种晶体尺度记录的数据纳入热化学模型，以评估多巴岩浆系统的现状和重新隆起的驱动力。因此，限制岩浆过程在复活的储层中发生的时间尺度、条件和程度将对喷发预测做出根本性贡献，特别是当地球物理方法被挑战来描述熔体时，该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查进行评估，被认为值得支持的搜索.