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

岩基组装和成熟的火山探针：安第斯山脉中部奥坎基尔恰火山群中水晶货物的年龄和来源

• 批准号: 0711480
• 负责人: Anita Grunder
• 金额: $ 29.96万
• 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: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0711480&HistoricalAwards=false
• 关键词: Volcanic; Probe; Batholith; Assembly; Maturation

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.

知识价值。本文提出对安第斯山脉中部的Aucanquilcha火山群（AVC）进行重点研究，以了解晶体再循环和地壳杂化在控制长寿命岩浆系统岩浆演化中的作用。AVC由大约15座主要的安山岩和英安岩火山组成，这些火山在11万年的时间里形成。这种岩浆活动很可能与一个复杂的岩浆储层系统的演化有关，但这种系统如何演化以及它们如何改变或与地壳相互作用是尚未解决的问题。例如，岩浆是来自一个长期存在的储层，还是来自一系列离散的岩浆体？为了回答这个问题，建议对跨越火山场生命的代表性喷发矿床的斑晶种群进行表征。晶体群的年龄和来源将通过多种分析方法进行评估，包括锆石的U-Pb定年、锆石中的ti -in- thermometry、带状斜长石和磷灰石晶体的原位Sr同位素分析以及块状岩石的Sr- nd和Pb同位素组成。这些数据将揭示岩浆源的热演化、新旧岩浆之间的混合以及岩浆与地壳寄主岩之间的混合。更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SERNAGEOMIN的智利地质学家的国际合作。这项工作将有助于了解相关的斑岩铜矿化，并将与该地区的区域测绘和岩石学研究相结合。除了科学出版物外，研究成果还将被pi纳入教材。