Carbon dioxide in ultrapotassic silicate melts: mechanisms and rates of magma degassing and their influence on the intensity and style of volcanic eruptions.

超钾硅酸盐熔体中的二氧化碳：岩浆脱气的机制和速率及其对火山喷发强度和类型的影响。

• 批准号: 390873681
• 负责人: Dr. Burkhard Schmidt
• 金额: --
• 依托单位: Osservatorio Vesuviano
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/390873681?language=en
• 关键词: Carbon; dioxide; ultrapotassic; silicate; melts

Some of the most dangerous active volcanic areas in the world are characterized by magmatic plumbing systems emplaced within carbonate substrata: e.g. Mt. Etna, Mt. Vesuvius, Campi Flegrei and Colli Albani (Italy); Popocatépetl and Colima (Mexico); Merapi (Indonesia). The magma-carbonate interaction during contact metamorphic reactions results in a significant presence of carbon dioxide in those systems. So far, experimental data on magma properties of CO2 dominated magmas are missing. Determining the role of CO2 in the dynamics of magma ascent is a pre-condition for understanding and modeling of degassing and fragmentation processes not only at CO2 dominated volcanic systems but also at depth, where the relatively insoluble CO2 may play an important role beside water. Furthermore, this information are crucial to unambiguously define the role played by different volatiles in the silicate melts.This work will be performed on ultrapotassic magma suites (e.g. foiditic and phonolitic melts), characteristic of volcanic systems emplaced in carbonate-rich crust. CO2-H2O solubility experiments and CO2 diffusion experiments will be carried out in high pressure-high temperature apparatus to investigate magma properties at near equilibrium conditions. The acquired information will be useful to understand and describe long-term processes at depth (i.e. in the magma chamber) such as crystallization, magma differentiation or wall rock assimilation. In addition, decompression experiments in high pressure-high temperature apparatus able to perform a controlled decompression will be performed to study the kinetics of short to intermediate term processes such as CO2 bubble nucleation and growth. Phase relation and degassing processes may significantly influence rheological magma properties and thus fragmentation and eruptive style of volcanoes. The obtained experimental data will be compared with the information recorded in the textural patterns and in the chemistry of the natural samples from Colli Albani and Mt. Vesuvius volcanoes.Our experimental data will provide useful constrain for volcanic hazard assessment at high risk volcanic areas.

世界上一些最危险的活火山地区的特点是碳酸盐岩地层内有岩浆管道系统：例如埃特纳火山、维苏威火山、Campi Flegrei 和 Colli Albani（意大利）和 Colima（墨西哥）； ）。接触变质反应期间的岩浆-碳酸盐相互作用导致这些系统中大量存在二氧化碳。到目前为止，关于以二氧化碳为主的岩浆特性的实验数据仍然缺失，确定二氧化碳在岩浆上升动力学中的作用是理解和模拟二氧化碳为主的火山系统的脱气和破碎过程的先决条件。此外，这些信息对于明确定义硅酸盐熔体中不同挥发物所起的作用至关重要。这项工作将在以下区域进行。超钾质岩浆组（例如富钙质熔体和声石熔体）、富含碳酸盐地壳中火山系统的特征，将在高压高温装置中进行CO2-H2O溶解度实验和CO2扩散实验，以研究近平衡条件下的岩浆性质。获得的信息将有助于理解和描述深度（即岩浆房中）的长期过程，例如结晶、岩浆分化或围岩此外，将在能够进行受控减压的高压高温装置中进行减压实验，以研究二氧化碳气泡成核和生长等可能显着影响流变学的动力学。岩浆特性以及火山的破碎和喷发方式将与来自阿尔巴尼山和山的天然样本的结构模式和化学成分中记录的信息进行比较。维苏威火山。我们的实验数据将为高风险火山地区的火山灾害评估提供有用的约束。