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.

火山爆发影响着从地方到全球的社会。在当地和地区，社会和基础设施可能会遭到破坏。在全球范围内，这样的喷发可能会影响全球气候。历史上的例子包括坦博拉1815年和皮纳图博1991年。这些火山喷发发生在俯冲带，也就是地球板块交汇的地方。它们还形成火山口，岩浆室上方的地面坍塌形成一个巨大的凹陷。这种喷发以每世纪几次的频率发生，因此引起了社会的关注。在努力了解这种火山口火山的潜在威胁时，一个关键问题是“可喷发的岩浆体是如何聚集在一起的，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Cerro Blanco火山综合体(CBVC)。在这里，过去30,000年来的三次主要爆炸性喷发记录了一座活火山的间歇性发展。该项目将利用岩浆中生长的矿物的化学和年龄来揭示CBVC岩浆的生长、发育和持久性。将使用最新的方法对火山喷发中的个别矿物进行年龄测定和地球化学研究。将开发分析和建模这些数据的新方法。该项目有许多更广泛的影响，使学科和社会受益。高级科学团队是国际化和多元化的。这些资深科学家将指导一名来自阿根廷的初级科学家。一名本科生研究人员也将深入参与这个项目。该项目的成果将支持当地旅游业，并成为未来火山科学家实地研讨会的重点。该项目将限制在安第斯山脉中央火山带聚集并维持3万年强烈流纹岩火山活动的岩浆过程和流动。与世界各地与俯冲有关的破火山口火山有关的两个假说将得到检验：1)导致CBVC发展和演化的岩浆通量是世界范围内与弧有关的岩浆通量的典型；以及2)CBVC是幕式建造的复合弧状岩体的表面表达。该项目第一阶段将利用U系列和锆石U-Th/He耦合测年(ZDD)来精炼CBVC的喷发频率和节奏，并圈定CBVC的时空发展。然后，这个框架将被用来探索岩浆的演化、发展和岩浆杂岩的现状，直接检验这两个假说。为了做到这一点，还将收集锆石中的微量元素和氧同位素，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。这项研究的成果将包括对这些系统进行热化学模拟的新努力，这将促进对岩浆如何在浅地壳喷发前储存的理解，并形成历史时期发生的、因此具有直接社会意义的规模的灾难性喷发。这些知识也是熔岩是如何建造的，地壳如何演化，以及矿体是如何形成的。该项目以国际合作为特色，提供了将年轻火山系统的年龄测定和地球化学联系起来的最新方法。一个由资深科学家组成的多元化团队将指导一名来自阿根廷的早期职业研究人员和本科生研究人员，以确保解决人力资本开发、知识转移和本科生研究经验的更广泛影响。这一奖项反映了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。