Volcanic Probe of Batholith Assembly and Maturation: Age and Source of Crystal Cargo in the Aucanquilcha Volcanic Cluster, Central Andes

智力上的优点。对安第斯山脉中部的奥坎奎尔查火山群(AVC)进行了重点研究，以了解晶体循环和地壳杂化在控制长寿岩浆系统的岩浆演化中的作用。AVC由大约15个主要的安山岩和英安岩火山组成，这些火山的形成时间超过了11英里。句号。这种岩浆作用很可能与一个复杂的岩浆储集层系统的演化有关，但这种系统如何演化以及它们如何修改或与地壳相互作用仍是悬而未决的问题。例如，岩浆是来自单一的长寿储集层，还是来自一系列离散的岩浆体？为了回答这个问题，有人建议描述横跨火山场生命周期的典型喷发沉积物的斑晶种群。年龄和晶群来源将通过多种分析方法进行评估，包括锆石U-Pb定年、锆石中钛测温、带状斜长石和磷灰石晶体的原位锶同位素分析以及块状岩石的锶-钕和铅同位素组成。这些数据将揭示岩浆源的热演化以及新旧岩浆之间的混合以及岩浆与其地壳寄主岩石之间的混合。广泛的影响包括对一名研究生和几名本科生的支持，以及与来自SERNAGEOMIN的智利地质学家的国际合作。这项工作将与了解相关的斑岩铜矿作用有关，并将与该地区的区域填图和岩石学研究相配合。除了科学出版物外，研究成果还将由私人督学编入教材。

Intellectual merit. A focused investigation of the Aucanquilcha Volcanic Cluster (AVC) of the central Andes is proposed to understand the roles of crystal recycling and crustal hybridization in controlling the magmatic evolution of long-lived magma systems. The AVC comprises some 15 major andesite and dacite volcanoes that developed over an 11 m.y. period. It is likely that this magmatism is related to evolution of a complex magma reservoir system, but how such systems evolve and how they modify or interact with the crust are unresolved questions. For example, are magmas derived from a single long-lived reservoir or from a sequence of discrete magma bodies? To answer this question, it is proposed to characterize the phenocryst populations of representative eruptive deposits spanning the life of the volcanic field. Ages and sources of crystal populations will be evaluated through multiple analytical approaches including U-Pb dating of zircons, Ti-in-zircon thermometry, in situ Sr isotopic analyses of zoned plagioclase and apatite crystals, and bulk rock Sr-Nd and Pb isotopic compositions. These data will reveal the thermal evolution of magma sources as well as mixing between new and old magma and between magmas and their crustal host rocks.Broader impacts include support of a graduate and several undergraduate students and international collaboration with Chilean geologists from SERNAGEOMIN. The work will be relevant to understanding related porphyry copper mineralization, and will tie in with regional mapping and petrologic studies in the region. In addition to scientific publications, research findings will be incorporated into teaching materials by the PIs.