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.

像多巴火山和黄石火山口这样的火山是地球上最严重的自然灾害：超级火山喷发的发生地，因此人们投入了大量精力来了解这些火山喷发的性质、它们的危害以及它们对社会造成的风险。然而，虽然现在人们已经很好地了解了超级喷发的形成过程，但人们对超级喷发之后发生的情况（称为复苏期）仍然知之甚少。这很重要，因为所有的活动都处于活跃状态。地球上的超级火山处于这种状态，但仍然构成重大危险，该项目旨在通过研究过去 200 万年来最大规模的超级火山爆发后的事件来填补这一知识空白，并提高我们评估超级火山未来危害和风险的能力。来自印度尼西亚多巴火山口的最年轻的多巴凝灰岩（YTT；距今约 74,000 年） 作为 NSF EAR 博士后研究员，Cisneros de León 博士将融入其中。记录在多巴喷发的微观晶体中的时间、化学和温度信息，以建立超级喷发后恢复过程中岩浆的物理和化学条件的历史，这种方法还将揭示自超级喷发以来的喷发历史，并允许估计。今天存在于多巴超级火山下方的可喷发岩浆量能够更好地评估未来风险。该提案的目标是利用多巴火山口作为天然实验室来解析岩浆过程的时间和空间尺度。这将通过使用锆石、铜长石、独居石、磷灰石、透钠石和石英整合岩石年代学、热年代学、扩散和热化学模型来破译这些晶相的互补记录，从而实现超级火山的复苏。火山口后管道系统及其在十年到千年时间尺度上的组成演变具体目标是 1) 开发一个综合的。基于多个辅助和主要矿物相记录的时间、温度和化学成分来研究所有尺度的喷发前硅质岩浆储层的岩石成因方法；2) 使用此信息推断喷发前岩浆储存的物理化学状态；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，本研究将应用惰性气体 40Ar/39Ar 和 (U-Th)/He 热年代学。利用锆石、独居石和磷灰石中的 Ar- 和 He- 的不同闭合温度来解决选定火山口后喷发的喷发火山喷发年龄、储存条件和喷出率。离子质谱 (SIMS) 和激光烧蚀电感耦合等离子体质谱 (LA-ICP-MS) 将用于辅助矿物相分析最后，来自各种晶体尺度记录的数据将被整合到热化学模型中，以评估多巴岩浆系统的当前状态以及复活的驱动力。因此，限制复活储层中岩浆过程发生的时间尺度、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难以描述特征时。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。