Collaborative Research: Experimental Investigation of Magmatic Processes at Volcan Quizapu

合作研究：基扎普火山岩浆过程的实验研究

• 批准号: 1717288
• 负责人: Philipp Ruprecht
• 金额: $ 4.77万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-03-31 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1717288&HistoricalAwards=false
• 关键词: Collaborative; Research; Experimental; Investigation; Magmatic

Volcanic eruptions taking place along subduction zones (arcs) are commonly interpreted as triggered by the influx of new magma to their shallow storage systems. This project aims to explore the late-stage changes in temperature, pressure, water content, and composition of arc magmas on the "crystal cargo" they carry, by testing the premise that the textures and compositions of erupted materials preserve this chronology. Comparison of experimental and natural samples will shed light on magma chamber and transit processes occurring between magma mixing and eruption.Two historical eruptions of Volcan Quizapu (Chilean Andes), one effusive and one explosive, have been characterized petrologically and geochemically in prior studies. Evidence points to a magmatic system of predominantly dacite with single-episode, eruption-triggering influxes of andesitic magma. The relative simplicity of these interactions makes Quizapu an ideal starting point for a targeted experimental study addressing questions related to magma mixing and ascent/eruption. Key lines of inquiry include constraining resorption/de-stabilization kinetics of plagioclase and amphibole in response to perturbation, as these minerals preserve evidence of magma storage conditions prior to eruption. The goals of this investigation are to (1) establish pre-eruption environmental conditions of Quizapu dacite and andesite, (2) examine response times of key thermobarometers and hygrometers through a series of step-heating experiments, (3) explore the formation conditions of sieve-textured plagioclase, and (4) broadly examine crystal-scale responses to thermodynamic perturbations through high-resolution chemical analysis and diffusion modeling. The results will have general implications for magma mixing processes among intermediate-composition arc magmas, not only because the recharge-triggered Quizapu events are typical of arc volcanoes, but also because the crystal-scale processes on which the study focuses (the influence of halogens on amphibole composition and stability, plagioclase dissolution kinetics upon heating, and formation of sieve-texture via several proposed mechanisms) are germane to a broad spectrum of magmatic settings.

沿着俯冲带（弧）发生的火山喷发通常被解释为由新岩浆流入其浅层储存系统引发。该项目旨在通过测试喷发物质的质地和成分保留这一年代学的前提，探索其携带的“水晶货物”上弧形岩浆的温度、压力、含水量和成分的后期变化。实验样品和自然样品的比较将揭示岩浆房以及岩浆混合和喷发之间发生的传输过程。基扎普火山（智利安第斯山脉）历史上的两次喷发，一次是喷发，一次是爆炸，在先前的研究中已经从岩石学和地球化学角度进行了表征。 有证据表明，岩浆系统主要由英安岩组成，并伴有单次喷发，引发安山岩浆涌入。 这些相互作用的相对简单性使 Quizapu 成为解决与岩浆混合和上升/喷发相关问题的有针对性的实验研究的理想起点。 关键的研究方向包括限制斜长石和角闪石响应扰动的再吸收/去稳定动力学，因为这些矿物保留了喷发前岩浆储存条件的证据。本次调查的目标是（1）建立 Quizapu 英安岩和安山岩喷发前的环境条件，（2）通过一系列逐步加热实验检查关键温湿度计和湿度计的响应时间，（3）探索筛状斜长石，(4) 通过高分辨率化学分析和扩散模型广泛检查晶体尺度对热力学扰动的响应。 这些结果将对中间成分弧岩浆之间的岩浆混合过程产生普遍影响，不仅因为补给触发的 Quizapu 事件是弧火山的典型现象，而且还因为该研究重点关注的晶体尺度过程（卤素的影响）角闪石的组成和稳定性、加热时的斜长石溶解动力学以及通过几种提出的机制形成筛网结构）与广泛的岩浆环境密切相关。

项目成果

Evidence for primitive magma storage and eruption following prolonged equilibration in thickened crust

加厚地壳长期平衡后原始岩浆储存和喷发的证据

• DOI: 10.1007/s00445-020-01406-3
• 发表时间: 2020-11
• 期刊: Bulletin of Volcanology
• 影响因子: 3.5
• 作者: Winslow, Heather;Ruprecht, Philipp;Stelten, Mark;Amigo, Alvaro
• 通讯作者: Amigo, Alvaro