Partitioning of sulfur and sulfur isotopes between fluids and melts - a key for understanding and monitoring of magmatic degassing

硫和硫同位素在流体和熔体之间的分配——理解和监测岩浆脱气的关键

基本信息

批准号：
164914959
负责人：
Professor Dr. Harald Behrens
金额：
--
依托单位：
Institut für Mineralogie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2014-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/164914959?language=en
关键词：
Partitioning sulfur isotopes between fluids

项目摘要

Understanding of degassing of magmas is central to monitoring and forecasting of volcanic eruptions. Sulfur is a major volatile released from magmas after decompression and the improved understanding of sulfur isotope geochemistry is vital to volcanic hazard mitigation, because sulfur partitions strongly into the vapor in oxidized melt-vapor systems. The determi2 nation of the sulfur isotope geochemistry in gases from arc magmas is extremely useful to constrain sulfur fluxes in the crust and the underlying mantle wedge. However, this requires a good knowledge (1) of the sulfur isotope-characterization of primitive melts, (2) of the behavior of sulfur during decompression of magmas as well as during magma-fluid interactions and (3) of the distribution of sulfur isotopes between phases (minerals, melts, fluids). In the proposed research we want to investigate experimentally the distribution of sulfur and of sulfur isotopes between liquids and fluids both under near-equilibrium conditions (long term experiments) and under kinetic control (rapid decompression, rapid cooling). Base compositions for this pioneering study will be in the compositional range from dacite to andesitic basalt which have relevance for arc volcanism and can dissolve sufficient sulfur for reliable quantitative analyses. The experimental products will be analyzed with various analytical techniques including SIMS and Laser Ablation-ICPMS. One aim of the project will be to improve these techniques for measurement of sulfur isotopes at low sulfur concentrations in glasses. The experimental results will be used to interpret glass inclusion data which will be mainly obtained by our cooperation partner Charles Mandeville (American Museum of Natural History (AMNH), New York). Combination of the data will be used to develop degassing scenarios for selected volcanoes.

了解岩浆的脱气是监测和预测火山喷发的核心。硫是减压后从岩浆中释放出来的一种主要挥发性，对硫同位素地球化学的了解对减轻火山危害至关重要，因为在氧化的熔融蒸发系统中，硫分配强烈地进入蒸气中。来自电弧岩浆气体中硫同位素地球化学的确定2对约束地壳和下面地幔楔中的硫通量非常有用。但是，这需要对原始熔体的硫同位素 - 特征的良好知识（1），（2）在岩浆解压缩期间以及岩浆液体相互作用期间的硫行为以及（3）硫酸异位素之间的分布（3）阶段（矿物质，熔体，液体）之间的硫同位素分布。在拟议的研究中，我们希望在近平衡条件下（长期实验）和动力学对照（快速减压，快速冷却）下，在液体和液体之间的硫和流体之间的硫和流体之间的分布进行实验研究。这项开创性研究的基础组成将在与弧火山弧相关的底层底层的组成范围内，并且可以溶解足够的硫来进行可靠的定量分析。实验产品将通过包括SIMS和激光消融-ICPM在内的各种分析技术进行分析。该项目的目的之一是改进这些技术，用于测量玻璃中低硫浓度的硫同位素。实验结果将用于解释玻璃包容性数据，这些数据将主要由我们的合作合作伙伴查尔斯·曼德维尔（美国自然历史博物馆（AMNH），纽约）获得。数据的组合将用于开发选定火山的脱气场景。