RUI: Collaborative Research: The Roles of Incremental Input, Magma Chamber Processes and Eruption on the Construction of the Bimodal Vinalhaven Plutonic-Volcanic Complex, Maine

这项对暴露在缅因州海岸的维纳尔黑文侵入岩和相关火山岩的研究，试图了解(1)这种双峰式的深成-火山杂岩是如何构造的，以及(2)输入、岩浆室过程和喷发损失如何影响维纳尔黑文花岗岩的成分和结构。该杂岩中既有深成岩，有广泛的岩浆室作用证据，也有同时代的火山岩，是检验岩体增量增长模型的理想岩浆系统。高精度的锆石U-Pb年代学为岩体的形成和同时代火山岩的喷发提供了时间框架。前人的研究建立了镁铁质(87Sr/86SRI=0.70234；epsilon ND=+6)和长英质(87Sr/86SRI=0.70713；epsilon ND=-2)输入的高度对比的锶和钕同位素组成。这项研究将记录Vinalaven杂岩的岩浆演化，包括镁铁质和硅质补给、再生、结晶的历史，以及同时代火山岩的演化。密集的实地考察将与岩石学、全岩和矿物化学相结合。花岗岩中沉积特征的填图和研究将建立花岗岩的时空固结史。花岗岩、硅质进料岩和流纹岩的结晶历史将受到锆石、长石和石英成分分带的高分辨率成像的制约。最后，全岩的锶、钕、氢同位素组成和以前的锆石晶体/碎屑的氢同位素组成，结合岩石化学数据，应该能够深入了解源区、岩浆室过程、硅质和镁铁质输入以及演化流纹岩的喷发对花岗岩化学和同位素组成的相对影响。这项研究的结果将有助于确定深成和火山过程和产品之间的岩石学联系。它还将提供对火山学家推断的一些岩浆室过程的深成观点，包括补充、岩浆混合和混合、花岗岩晶体碎屑的再生、对流搅拌和分馏。地质年代学数据将对这些过程的运行速度提供基本限制，并允许与类似火山中心的时间尺度进行直接比较。最后，这项研究将评估源区和岩浆室过程对花岗岩的地球化学和同位素组成的相对贡献，并将为解释深成和火山系统的全岩同位素数据提供新的见解。

This proposed research on the Vinalhaven intrusion and related volcanic rocks, exposed on the coast of Maine, attempts to understand (1) how this bimodal, plutonic-volcanic complex was constructed, and (2) how input, magma chamber processes and loss by eruption affected the compositions and textures of the Vinalhaven granite. This complex, which contains both plutonic rocks with evidence for a wide range of magma chamber processes and coeval volcanic rocks, is an ideal magmatic system in which to test the model of incremental pluton growth. High-precision U-Pb zircon geochronology provides a time frame for pluton construction and the eruption of coeval volcanic rocks. Prior studies established highly contrasted Sr and Nd isotopic compositions of mafic (87Sr/86Sri = 0.70234; epsilon Nd = +6) and felsic (87Sr/86 Sri = 0.70713; epsilon Nd = -2) input. The research will document the magmatic evolution of the Vinalhaven complex, including the history of mafic and silicic replenishment, rejuvenation, crystallization, and the evolution of coeval volcanic rocks. Intensive fieldwork will be combined with petrography, whole-rock and mineral chemistry. Mapping and study of depositional features in the granite will establish the spatial and temporal consolidation history of the granite. The crystallization history of granite, silicic feeders and rhyolite will be constrained by high-resolution imaging of compositional zoning in zircon, feldspar and quartz. Finally, whole rock Sr, Nd and Hf isotopic compositions and the Hf isotopic composition of previously dated zircon crystals/fragments, combined with petrochemical data, should provide insights into the relative influences of the source region, magma chamber processes, silicic and mafic input, and the eruption of evolved rhyolite on the chemical and isotopic composition of the granite. The results of this study will help identify firm petrologic links between plutonic and volcanic processes and products. It will also provide a plutonic perspective on a number of magma chamber processes inferred by volcanologists, including replenishment, magma mingling and mixing, rejuvenation of granitic crystal mush, convective stirring, and fractionation. Geochronologic data will provide fundamental constraints on the rates at which these processes operate and permit direct comparison to the timescales of analogous volcanic centers. Finally, this research will assess the relative contributions of the source region and magma chamber processes to the geochemical and isotopic composition of granite and should provide fresh insights into the interpretation of whole-rock isotopic data from both plutonic and volcanic systems.