Collaborative Research: 4-D Assessment of the Earliest Magmatism in a Continental Margin Arc

0000719 Beard0001004 Crawford0001102 Sinhad0001004 Crawford0001102随着汇聚构造将外来物质吸积到大陆边缘，发生了一些重要的条件变化，其中一些导致了岩浆的产生，随后又参与了吸积的持续结构发展。由于英云闪长岩体通常是以大陆边缘弧共生的形式产生的，它们的组成提供了关于源区P-T-X-H2O条件的信息，并结合组构和构造数据，为岩浆在穿越和侵位于地壳时可能导致化学变质的运输和侵位过程提供了约束。该项目将利用阿拉斯加东南部雷维拉吉多岛上的一套英云母深成岩浆，这些深成岩浆记录了大陆弧岩浆活动的早期阶段。预计结果将详细说明和追踪这些岩浆在这种汇聚环境中的起源、改造和构造相互作用。

0000719 Beard0001004 Crawford0001102 SinhaAs exotic material accretes to a continental margin by convergent tectonics, a number of important changes in conditions occurs, some of which lead to production of magma that subsequently becomes involved in the ongoing structural development of the accretion. As tonalitic plutons are commonly generated as continental margin arcs accrete, their composition provides information about the P-T-X H2O conditions of the source region, and combined with fabric and structural data, provide constraints for the transport and emplacement processes that might lead to chemical modification of magmas as they traverse and are emplaced in the crust. The project will utilize a suite of tonalitic plutons on Revillagigedo Island in southeastern Alaska that record early stages of continental arc magmatism. Results are expected to detail and track the origin, modification and tectonic interactions of these magmas in this convergent setting.