Silicic melt evolution in the early Izu-Bonin arc recorded in detrital zircons

碎屑锆石记录的早期伊豆-小笠宁岛弧硅质熔体演化

• 批准号: 1558830
• 负责人: Andrew Barth
• 金额: $ 10.1万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1558830&HistoricalAwards=false
• 关键词: Silicic; melt; evolution; early; Izu

Understanding the movement of tectonic plates across Earth's surface and the eventual return of these plates to the interior of our planet is central to our knowledge of Earth and its natural hazards such as earthquakes, tsunamis, and volcanic eruptions. This research focuses on understanding the formation, growth and eventual demise of volcanoes that mark the process of subduction, where tectonic plates return to Earth's interior. Minerals recovered from deep beneath the western Pacific Ocean floor by the International Ocean Discovery Program will be examined to decipher the history of volcano growth above an evolving subduction zone. The goals of the research are to use the chemistry of these minerals, called zircons, to better understand the life cycle of volcanoes, especially the timing of explosive volcanic eruptions. This research involves strong integration of research and education by involving undergraduate university students both in the laboratory and in field-based research projects at similar ocean floor volcanic systems that are now exposed on land in the Sierra Nevada mountains in the western United States. The goal of this study is to better understand the generation of silicic melts in a new and evolving intra-oceanic volcanic arc by searching for petrologic links between silicic volcanism and tonalitic arc plutonism and using this to better understand the evolution of the related magmatic processes through time. The primary goal of the research is to test whether (or to what extent) detrital zircons in drill cores, recovered by the International Ocean Drilling Program Expedition 351 and other legacy ocean drilling cores from a relatively primitive oceanic arc setting, record the regional and/or secular variation in silicic melts that crystallized magmatic zircon. Geochronology and trace element geochemistry of the zircons will allow comparisons between the thermal and melt chemical evolution recorded by arc-derived detrital zircons and by igneous zircons recovered in dredge samples of contemporaneous arc tonalite. This study will also generate an internally-consistent database of geochemical parameters for arc-derived zircons from a compositional range of marine arcs that will be useful for comparative zircon provenance studies, as these studies evolve to more commonly include key geochemical provenance indicators.

了解构造板块穿过地球表面的运动以及这些板块最终返回地球内部的过程，是我们了解地球及其地震、海啸和火山喷发等自然灾害的核心。这项研究的重点是了解标志着俯冲过程的火山的形成、增长和最终消亡，在俯冲过程中，构造板块回到地球内部。将对国际海洋发现计划在西太平洋海底深处发现的矿物进行研究，以破译俯冲演化带上方火山生长的历史。这项研究的目的是利用这些被称为锆石的矿物的化学成分，更好地了解火山的生命周期，特别是火山爆发的时间。这项研究涉及研究和教育的紧密结合，让本科生参与实验室和类似海底火山系统的实地研究项目，这些火山系统现在暴露在美国西部内华达山脉的陆地上。这项研究的目的是通过寻找硅质火山作用和英云闪长岩弧深成作用之间的岩石学联系，并利用这一联系来更好地理解相关岩浆过程随时间的演化，从而更好地理解在新的和不断演变的大洋内火山弧中硅质熔融的产生。这项研究的主要目标是测试国际大洋钻探计划351和其他传统大洋钻探岩芯从相对原始的洋弧环境中发现的钻探岩芯中的碎屑锆石是否(或在多大程度上)记录了结晶岩浆锆石的硅质熔体中的区域和/或长期变化。锆石的地质年代学和微量元素地球化学可以比较弧源碎屑锆石记录的热化学演化和熔融化学演化，以及在同时代弧状英云闪长岩挖矿样品中发现的火成锆石。这项研究还将从一系列海洋弧形成分中为弧源锆石生成一个内部一致的地球化学参数数据库，这将有助于比较锆石源区的研究，因为这些研究已发展到更普遍地包括关键的地球化学源区指标。