Mantle Signals in Arcs: Transport Models From Geochemistry and Seismicity

弧中的地幔信号：来自地球化学和地震活动的传输模型

• 批准号: 1426820
• 负责人: Philipp Ruprecht
• 金额: $ 22.06万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-02-01 至 2017-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1426820&HistoricalAwards=false
• 关键词: Mantle; Signals; Arcs; Transport; Models

The proposed study will explore magma transport rates in the middle to lower crust of convergent margin volcanoes and therefore address one of the most fundamental questions in geodynamics: How do magmas move from their source region in the mantle wedge to the surface? Furthermore, results from this study will provide first-order controls on arc magma petrogenesis, connecting the mantle source and melting process with the crustal plumbing system as well as provide insights on the aggregation of mantle-derived melts beneath arc volcanoes. The project is designed to use an integrative approach combining constraints from geochemistry, seismology, and fluid dynamics. The project will lead to a better understanding of magma transport beneath active volcanoes and improve our interpretation of monitoring dataset from such volcanoes.Current models for magma transport in convergent margins suggest the prolonged storage and evolution of mantle-derived melts in the crust. This project will test whether a fast mode of magma transport even for large, long-lived arc magma systems exists and what conditions may facilitate such rapid ascent from the mantle to the surface. The time-integrative nature of geochemical data often precludes a direct comparison to geophysical signals that record transient processes. However, geochemical speedometers employing fast elemental diffusion in zoned magmatic crystals may bridge this observational gap and advance the application of geochemical tools to short time scale magmatic processes otherwise only investigated through geophysics. Such techniques have been successfully employed for near-surface magmatic processes; this projects aims at extending such approaches to the entire crustal magma ascent path.

拟议的研究将探讨岩浆运输率在中地壳到下地壳的会聚边缘火山，因此解决地球动力学中最基本的问题之一：岩浆如何从其源区地幔楔表面？此外，从这项研究的结果将提供一级控制弧岩浆岩石成因，连接地幔源和熔融过程与地壳管道系统，以及提供见解下弧火山幔源熔体的聚集。该项目旨在使用综合方法，结合地球化学，地震学和流体动力学的约束。该项目将使我们更好地了解活火山下的岩浆输送，并改进我们对此类火山监测数据集的解释。目前会聚边缘岩浆输送的模型表明，地壳中幔源熔体的长期储存和演化。该项目将测试是否存在一种快速的岩浆运输模式，即使是大型的、寿命长的弧岩浆系统，以及什么条件可能促进这种从地幔到地表的快速上升。地球化学数据的时间综合性质通常排除了与记录瞬态过程的地球物理信号的直接比较。然而，地球化学速度计采用快速元素扩散在分区岩浆晶体可能会弥合这一观测差距，并推进应用地球化学工具，否则只能通过地球物理研究的短时间尺度的岩浆过程。这种技术已成功地用于近地表岩浆过程;该项目旨在将这种方法推广到整个地壳岩浆上升路径。