Collaborative Research: Experimental Investigation of Magmatic Processes at Volcan Quizapu

沿着俯冲带（弧）发生的火山爆发通常被解释为新岩浆涌入其浅层储存系统所触发。该项目旨在通过测试喷发物质的结构和成分是否保留了这种年表，来探索弧岩浆在其携带的“晶体货物”上的温度、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室和在岩浆混合和喷发之间发生的过渡过程。智利安第斯山脉奎兹卡普火山历史上的两次喷发，一次是热流喷发，一次是爆发性喷发，已经在岩石学和地球化学上进行了研究。有证据表明，这是一个以英安岩为主的岩浆系统，有单次触发喷发的安山岩岩浆流入。这些相互作用相对简单，使Quizapu成为解决岩浆混合和上升/喷发相关问题的有针对性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洞在扰动作用下的吸收/去稳定动力学，因为这些矿物保存了喷发前岩浆储存条件的证据。本研究的目标是：(1)建立Quizapu英安岩和安山岩喷发前的环境条件；(2)通过一系列阶梯加热实验研究关键温压计和湿度计的响应时间；(3)探索筛状斜长石的形成条件；(4)通过高分辨率化学分析和扩散模型广泛研究晶体尺度对热力学扰动的响应。这一结果将对中等成分弧岩浆的岩浆混合过程具有普遍意义，不仅因为充注触发的Quizapu事件是典型的弧火山事件，而且因为研究重点的晶体尺度过程(卤素对角闪洞组成和稳定性的影响，加热后斜长石溶解动力学，通过几种提出的机制，筛状结构的形成与广泛的岩浆环境密切相关。

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.