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; 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跃火山区的特征是岩浆底层内的岩浆管道系统：例如埃特纳山，维苏威山，坎皮·弗莱格里和科利·阿尔巴尼（意大利）； Popocatépetl和Colima（墨西哥）；梅拉皮（印度尼西亚）。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二氧化碳的显着存在。到目前为止，缺少有关CO2主导岩浆的岩浆性能的实验数据。确定二氧化碳在岩浆上升动力学中的作用是理解和建模脱气和破碎过程的前提，不仅在二氧化碳占主导的火山系统上，而且在深度处，相对不溶性二氧化碳可能在水旁边起重要作用。此外，这些信息对于明确定义了硅胶熔体中不同挥发性起的作用至关重要。这项工作将以超质岩浆套件（例如叶石和光石化熔体）进行，这是在碳酸盐富含碳酸盐构成的地壳中的火山系统的特征。 CO2-H2O溶解度实验和CO2差异实验将在高压高温设备中进行，以研究近乎平衡条件下的岩浆性能。获得的信息将有助于理解和描述深度（即在岩浆腔中）的长期过程，例如结晶，岩浆分化或壁岩同化。此外，将在高压高温设备上进行控制的解压缩实验，以研究短至中等任期过程的动力学，例如CO2气泡成核和生长。相位关系和脱气过程可能会显着影响流变学岩浆特性，从而碎片化和火山的喷发风格。将获得的实验数据与纹理模式中记录的信息以及来自Colli Albani和Vesuvius火山的天然样品的化学性质进行了比较。我们的实验数据将为高风险火山区域的火山危害评估提供有用的约束。