Pre-eruptive magma assembly, evolution and associated magma fluxes at arc calderas: insights from the active Cerro Blanco Volcanic Complex, Catamarca, Argentina.

弧火山口喷发前的岩浆聚集、演化和相关岩浆通量：来自阿根廷卡塔马卡活跃的塞罗布兰科火山群的见解。

• 批准号: 2243737
• 负责人: Shanaka de Silva
• 金额: $ 38.03万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2243737&HistoricalAwards=false
• 关键词: Pre; eruptive; magma; assembly; evolution

Explosive volcanic eruptions affect society from local to global scale. Locally and regionally, society and infrastructure may be devastated. Globally, such eruptions can affect global climate. Historic examples include Tambora 1815 and Pinatubo 1991. These eruptions occur at subduction zones, where Earth’s tectonic plates converge. They also form calderas, where the ground above the magma chamber collapses to produce a big depression. Such eruptions have occurred at a frequency of several per century, so they are of concern to society. A key question in the efforts to understand the potential threat from such caldera volcanoes is “how are eruptible bodies of magma assembled and for how long do they persist?”. To answer this question, the project will focus on the currently active Cerro Blanco Volcanic Complex (CBVC) in Catamarca, Argentina. Here, three major explosive eruptions in the last ~30,000 years record the episodic development of an active caldera volcano. The project will reveal the growth, development, and persistence of magma at the CBVC using the chemistry and age of minerals that grew in the magma. The latest approaches to age dating and geochemistry of individual minerals from the eruptions will be used. New ways of analyzing and modeling these data will be developed. The project has many broader impacts that benefit the discipline and society. The senior science team is international and diverse. These senior scientists will mentor a junior scientist from Argentina. An undergraduate researcher will also be deeply involved in this project. The outcomes of this project will support the local tourism industry and be the focus of a future field workshop for volcano scientists.This project will constrain the magmatic processes and fluxes that have assembled and sustained a 30,000-year locus of intense rhyolitic volcanism in the Central Volcanic Zone of the Andes. Two hypotheses relevant to subduction-related caldera volcanoes worldwide will be tested: 1) The magmatic flux that led to the development and evolution of the CBVC is typical of arc-related magmatic fluxes worldwide; and 2) The CBVC is the surface expression of an episodically built composite arc pluton. The first phase of the project will utilize coupled U-series and U-Th/He in zircon (Zircon Double Dating or ZDD) to refine the eruptive frequency and tempo of the CBVC and delineate the spatiotemporal development of the CBVC. This framework will then be used to probe the magmatic evolution, development, and current state of the magmatic complex, directly testing the two hypotheses. To do this, trace elements and O-isotopes in zircon will also be collected and integrated with melt chemistry, rhyolite-MELTS, and thermochemical modeling of zircon ages. The outcomes of the study will include new efforts in thermochemical modeling of these systems that will advance the understanding of how magma is stored pre-eruption in the shallow crust and builds up to catastrophic eruptions of a scale that have occurred in historic times and are therefore of immediate social relevance. This knowledge is also fundamental to how batholiths are constructed, the earth’s crust evolves, and how ore bodies form. The project features international collaborations that provide access to the newest approaches to link age dating and geochemistry of young volcanic systems. A diverse team of senior scientists will mentor an early career researcher from Argentina and undergraduate researchers to ensure that broader impacts of human capital development, knowledge transfer, and research experience for undergraduates are addressed. Outreach to local tourism efforts, and a future field workshop round out the broader impacts.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.

火山喷发从局部到全球范围都会影响社会和基础设施。在全球范围内，此类喷发可能会影响全球气候。历史上的例子包括 1815 年的坦博拉火山和 1991 年的皮纳图博火山。这些火山喷发发生在地球构造所在的俯冲带。它们也会形成火山口，岩浆塌陷室上方的地面会产生这样的火山喷发。每个世纪都会发生几次，因此，在了解此类破火山口火山潜在威胁的过程中，一个关键问题是“可喷发的岩浆体是如何聚集的以及它们会持续多久？”为了回答这个问题，该项目将重点关注阿根廷卡塔马卡目前活跃的塞罗布兰科火山群 (CBVC)，这里记录了过去约 30,000 年来的三次大规模爆发性喷发。该项目将利用岩浆中生长的矿物的化学成分和年龄来揭示 CBVC 岩浆的生长、发育和持久性，并将使用对喷发中的单个矿物进行年龄测定和地球化学的最新方法。该项目将开发对这些数据进行分析和建模的新方法，从而造福于学科和社会。这些资深科学家还将指导一名来自阿根廷的初级科学家。深入参与此事该项目的成果将支持当地的旅游业，并成为火山科学家未来实地研讨会的重点。该项目将限制岩浆过程和通量，这些岩浆过程和通量已聚集并维持了 30,000 年的强烈流纹岩火山活动。安第斯山脉中央火山带将测试与全球俯冲相关火山口火山有关的两个假设：1）导致 CBVC 发展和演化的岩浆通量是典型的全球范围内与弧相关的岩浆通量；以及 2) CBVC 是幕式复合弧岩体的表面表现，该项目的第一阶段将利用锆石中的 U-系列和 U-Th/He（锆石双重测年或 ZDD）。 ）以细化 CBVC 的喷发频率和速度，并描绘 CBVC 的时空发育，然后该框架将用于探测岩浆演化、发育和发育。为了直接检验这两种假设，我们还将收集锆石中的微量元素和 O 同位素，并将其与熔体化学、流纹岩熔体和锆石年龄的热化学模拟相结合。研究将包括对这些系统进行热化学建模的新努力，这将增进人们对岩浆如何在喷发前储存在浅层地壳中以及如何形成历史时期发生过的大规模灾难性喷发的理解。因此，这些知识对于岩基的构造、地壳的演化以及矿体的形成也至关重要。该项目的特点是国际合作，提供将年轻火山的年龄测定和地球化学联系起来的最新方法。由资深科学家组成的多元化团队将指导来自阿根廷的早期职业研究员和本科生研究人员，以确保本科生的人力资本开发、知识转移和研究经验对当地旅游业和未来领域的影响得到更广泛的影响。研讨会回合这反映了 NSF 的法定使命，并且通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。