• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Experiment vs nature: Using amphiboles to test models of magma storage and pre-eruptive magma dynamics preceding the 2006 eruption of Augustine Volcano, Alaska.
【24h】

Experiment vs nature: Using amphiboles to test models of magma storage and pre-eruptive magma dynamics preceding the 2006 eruption of Augustine Volcano, Alaska.

机译：实验与自然：在2006年阿拉斯加的奥古斯丁火山爆发之前，使用闪石来测试岩浆储存和喷发前岩浆动力学的模型。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

This study investigates magmatic conditions preceding the 2006 eruption of Augustine Volcano through the use of amphibole compositions and textures. Due to their restricted stability region and common occurrence in calc-alkaline magmas, amphiboles are important for investigating pre-eruptive magmatic conditions at subduction zone volcanoes. Chapter 1 presents a study into geochemical and textural variations of natural amphibole phenocrysts in the erupted magmas. Magnesiohornblendes in the high- and low-silica andesites exhibit limited compositional variability. Intermediate-silica andesites and quenched mafic enclaves contain amphiboles that vary in composition and classification (magnesiohornblende-magnesiohastinsitetschermakite). Compositional variations are controlled by temperature-dependent substitutions. Both high-and low-silica andesites represent magmas that were stored in the shallow crust at 4-8 km depth, remaining distinct due to a complex sub-surface plumbing system. Intermediate-silica andesites and quenched mafic inclusions represent newly formed hybrids of resident high- and low-silica andesite magmas and an intruding basalt. Chapter 2 presents the results of a phase equilibria study the refines the model for high-silica andesite storage. The natural phase assemblage was reproduced between 860-880°C and 120-200 MPa. Experimental plagioclase and groundmass glass compositions most closely replicate natural samples at ∼130-140 MPa. Estimated storage conditions fall within the ranges suggested by natural petrological data and modeled storage depths from geodetic data. The high temperature stability of experimental quartz and biotite (not identified in natural samples) may reflect the high f 02 of the Augustine system as well as the rapid kinetics associated with the crystal-poor sintered starting material of some experiments. Chapter 3 presents results of the first experimental study to target heating-induced amphibole reaction rim formation. Experiments show that reaction rims form on remarkably short timescales. They share mineralogical and textural features with natural reaction rims previously thought to represent decompression processes. Reaction rims cannot be simply classified on the basis of semi-quantitative observations. Rather, in-depth data collection (e.g. X-rap mapping), and the calculation of kinetic parameters (e.g. crystal nucleation rates), is necessary. Chapter 4 presents a new MATLAB® based program that performs mineral formula recalculations and the associated propagation of analytical uncertainty.
机译：这项研究通过使用闪石成分和质地调查了2006年奥古斯丁火山爆发之前的岩浆条件。由于其受限制的稳定区域以及在钙碱性岩浆中的普遍发生，两闪石对于调查俯冲带火山喷发前的岩浆条件很重要。第1章介绍了喷发岩浆中天然角闪石表晶的地球化学和质地变化的研究。高硅和低硅安山岩中的镁角质混合物显示出有限的组成变异性。中间硅质安山岩和淬火的镁铁质飞地含有闪石，闪石的组成和类别各不相同（magnesiohornblende-magnesiohastinsitetschermakite）。成分变化由温度依赖性取代控制。高硅质和低硅质安山岩都代表岩浆，这些岩浆以4-8 km的深度存储在浅层地壳中，由于复杂的地下管道系统，它们保持了明显的区别。中硅质安山岩和淬火镁铁质夹杂物代表了高，低硅质安山岩岩浆和侵入玄武岩的新形成的杂化物。第2章介绍了相平衡研究的结果，完善了高硅质安山岩存储模型。在860-880°C和120-200 MPa之间复制了自然相。实验斜长石和磨碎的玻璃成分最能复制约130-140 MPa的天然样品。估计的储藏条件在自然岩石学数据和根据大地测量数据模拟的储藏深度所建议的范围内。实验石英和黑云母的高温稳定性（在天然样品中未发现）可能反映出奥古斯丁体系的高f 02以及某些实验中与晶体贫乏的烧结原料相关的快速动力学。第三章介绍了针对加热引起的角闪石反应边缘形成的第一个实验研究的结果。实验表明，反应边缘在非常短的时间内形成。它们与以前认为代表减压过程的自然反应边缘具有相同的矿物学和质地特征。反应边缘不能简单地基于半定量观测进行分类。而是需要深入的数据收集（例如X-rap映射）和动力学参数的计算（例如晶体成核速率）。第4章介绍了一个新的基于MATLAB®的程序，该程序执行矿物配方的重新计算以及相关的分析不确定度的传播。

著录项

  • 作者

    Henton, Sarah Massey.;

  • 作者单位

    University of Alaska Fairbanks.;

  • 授予单位 University of Alaska Fairbanks.;
  • 学科 Petrology.
  • 学位 Ph.D.
  • 年度 2013
  • 页码 147 p.
  • 总页数 147
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号