Pre-eruptive conditions of the Campanian Ignimbrite eruption: Experimental constraints from phase equilibria and volatile solubility studies and its implication for the Campi Flegrei drilling project

了解和模拟Campi Flegrei火山和脱气过程的前提是：(1)确定岩浆储存条件；(2)了解岩浆补充过程，特别是岩浆室中注入的新岩浆的成分、温度和挥发分含量；(3)模拟岩浆上升过程中的脱气和结晶过程。到目前为止，使我们能够获得这一信息的高压和高温下的实验数据和热力学模型是稀缺的，不能直接应用于Campi Flegrei的声子系统和粗面系统。这些信息对于解释钻探产品和坎皮·弗莱格里(CFDDP)计划钻探现场的观察结果至关重要。在这项建议中，我们计划研究岩浆室(S)中的长期过程，如结晶和分异，以及在Campi Flegrei岩浆室喷发前新的岩浆输入所产生的短期过程(例如，脱气、混合、重新平衡)。Tübingen将探索岩浆从岩浆室上升到地表的过程(参见M.Nowak的应用)。采用不同的实验方法(即相平衡实验、动力学实验、含H_2O-CO_2-Cl-S混合挥发分在硅酸盐熔体中的溶解度实验)，研究了寒武纪Ignimbrite粗面岩和声光橄榄岩的岩浆储存条件、补充前端元岩浆的性质以及岩浆房中与熔体共存的流体的组成。对这些参数的了解对于理解和模拟岩浆流变性、碎片化和喷发方式的演化至关重要，这些演化记录在坎帕尼亚伊尼姆布里岩和火山灰的结构模式中。实验数据将为高危Campi Flegrei火山区的火山危险性评估提供有用的约束条件。

A prerequisite for the understanding and modeling of volcanic and degassing processes at Campi Flegrei is (1) the determination of magma storage conditions, (2) the understanding of magma replenishment processes, especially the composition, temperature, volatile contents of the new magmas injected in magmatic chamber and (3) the simulation of degassing and crystallization processes during magma ascent. So far experimental data and thermodynamic models at elevated pressures and temperatures, allowing us to gain this information, are scarce and can not be directly applied for the phonolitic and trachytic systems of Campi Flegrei. Such information is crucial for the interpretation of drilling products and of observations at the planned drilling site at Campi Flegrei (CFDDP). In this proposal we plan to investigate long term processes in the magma chamber(s), such as crystallization and differentiation, as well as short term processes resulting from new magma inputs occurring in the Campi Flegrei magma chamber prior to eruptions (e.g., degassing, mixing, re-equilibration). Processes during magma ascent from the magma chamber to the surface will be explored in Tübingen (see application of M. Nowak). Different experimental approaches (i.e. phase equilibria, kinetic experiments, solubility of mixed H2O-CO2-Cl-S-bearing volatiles in silicate melts) using trachytic and phonolitic rocks from the Campanian Ignimbrite will be used to investigate magma storage conditions, the properties of end-member magmas before replenishment, as well as the composition of fluids coexisting with melts in the magma chamber. The knowledge of these parameters is crucial to understand and model the evolution of rheological magma properties, fragmentation, eruptive style, which are recorded in the textural patterns of the Campanian Ignimbrite and of the volcanic ashes. The experimental data will provide useful constraints for volcanic hazard assessment at the high risk Campi Flegrei Volcanic Area.