Collaborative Research: Dynamics of caldera-scale rhyolitic magma systems

该项目的目的是建立一个新的认识的动态过程，创造大型流纹岩岩浆系统，并推动他们进入动荡和潜在的喷发状态。位于智利南安第斯山脉拉古纳德尔毛勒火山场（LdM）的自然实验室提供了一个绝好的机会来研究系统动力学，同时岩浆迁移、储层生长和地壳变形正在进行中。该项目将：(1)确定正在发生的动荡事件的原因，包括：(a)测量LdM下岩浆体的尺寸、深度和熔体比例；(b)估计这些参数如何随时间演变；(c)评估当前的变形和更长期（约2万年）的隆升是否反映了玄武岩对系统的补充；(2)综合岩石学和地质年代学资料，跟踪和模拟过去~10万年的结晶、冷却、岩浆混合和加热事件，并确定过去2.5万年流纹岩熔岩的爆发是否具有共同的浅源熔体，还是在地壳深处有更分散的起源；(3)建立耦合数值模型，将观测结果与各种时间尺度上多相岩浆-地壳系统的物理和化学联系起来。由于地球最终将经历另一次形成火山口的流纹岩喷发，因此有必要收集全面的信息并创建模型，以实际地解释导致这些破坏性事件的动力学。应对这一挑战需要理解：(1)缓慢的地质过程、岩浆条件和推动这些系统组装和生长的结构变化；(2)复杂的多相系统在漫长（数年至数千年）和短暂（数天至数月）的人类时间尺度上的动力学。目前缺乏对这些过程之间耦合的牢固把握，因为它们在时间和空间上的操作范围超过许多数量级。这个项目提供了一个独特的机会来研究这样一个系统的动力学，而岩浆迁移、储层生长和惊人的地壳变形目前正在进行中。通过观察和新颖的建模方法探索这一前沿将产生对系统动力学前所未有的洞察力。

The objective of this project is to build a new understanding of the dynamic processes that create large rhyolitic magma systems and drive them into states of unrest and potential eruption. The natural laboratory at the Laguna del Maule volcanic field (LdM) in the Southern Andes of Chile presents a remarkable opportunity to investigate system dynamics while magma migration, reservoir growth, and crustal deformation are currently underway. This project will: (1) Ascertain the cause of the ongoing episode of unrest, including: (a) gauging the dimensions, depth, and melt fraction of the magma body or bodies currently beneath LdM; (b) estimating how these parameters evolve with time, and (c) assessing whether both current deformation, and longer term, ~20,000 year, uplift, reflects replenishment of the system with basalt; (2) Integrate petrologic and geochronologic data to track and model crystallization, cooling, magma mixing and heating events over the past ~100,000 years, and to determine whether the eruptive flare-up of rhyolitic lavas during the last 25,000 years shares a common, shallow source of melt or has more diffuse origins deeper in the crust; and (3) Create coupled numerical models that will link the observations to the physics and chemistry of the multi-phase magma-crust system over a variety of timescales. Since Earth will eventually experience another caldera-forming rhyolitic eruption, there is a need to gather comprehensive information and create models that realistically account for the dynamics that lead to these destructive events. Meeting this challenge will require understanding: (1) the slow geologic processes, magmatic conditions, and structural changes that propel assembly and growth of these systems, and (2) the dynamics of a complex multiphase system on both long (years to millennia), and short (days to months) human time scales. A firm grasp on the coupling among these processes is currently lacking because they operate on scales ranging over many orders of magnitude temporally and spatially. This project affords a unique opportunity to investigate the dynamics of such a system while magma migration, reservoir growth, and astonishing crustal deformation are currently underway. Exploring this frontier through both observations and novel modeling approaches will yield unprecedented insight into system dynamics.