Morgavi D, Petrelli M, Vetere F P, González-García D, Perugini D
Department of Physics and Geology, Petro-Volcanology Research Group (PVRG), University of Perugia, Piazza Università, Perugia 06100, Italy.
Rev Sci Instrum. 2015 Oct;86(10):105108. doi: 10.1063/1.4932610.
A unique high-temperature apparatus was developed to trigger chaotic mixing at high-temperature (up to 1800 °C). This new apparatus, which we term Chaotic Magma Mixing Apparatus (COMMA), is designed to carry out experiments with high-temperature and high-viscosity (up to 10(6) Pa s) natural silicate melts. This instrument allows us to follow in time and space the evolution of the mixing process and the associated modulation of chemical composition. This is essential to understand the dynamics of magma mixing and related chemical exchanges. The COMMA device is tested by mixing natural melts from Aeolian Islands (Italy). The experiment was performed at 1180 °C using shoshonite and rhyolite melts, resulting in a viscosity ratio of more than three orders of magnitude. This viscosity ratio is close to the maximum possible ratio of viscosity between high-temperature natural silicate melts. Results indicate that the generated mixing structures are topologically identical to those observed in natural volcanic rocks highlighting the enormous potential of the COMMA to replicate, as a first approximation, the same mixing patterns observed in the natural environment. COMMA can be used to investigate in detail the space and time development of magma mixing providing information about this fundamental petrological and volcanological process that would be impossible to investigate by direct observations. Among the potentials of this new experimental device is the construction of empirical relationships relating the mixing time, obtained through experimental time series, and chemical exchanges between the melts to constrain the mixing-to-eruption time of volcanic systems, a fundamental topic in volcanic hazard assessment.
开发了一种独特的高温设备，以在高温（高达1800°C）下引发混沌混合。这种新设备，我们称之为混沌岩浆混合设备（COMMA），旨在对高温高粘度（高达10^6帕斯卡秒）的天然硅酸盐熔体进行实验。该仪器使我们能够在时间和空间上追踪混合过程的演变以及相关的化学成分调制。这对于理解岩浆混合的动力学和相关的化学交换至关重要。COMMA装置通过混合来自意大利埃奥利群岛的天然熔体进行测试。实验在1180°C下使用钾玄岩和流纹岩熔体进行，导致粘度比超过三个数量级。该粘度比接近高温天然硅酸盐熔体之间可能的最大粘度比。结果表明，所产生的混合结构在拓扑上与天然火山岩中观察到的结构相同，突出了COMMA作为初步近似复制在自然环境中观察到的相同混合模式的巨大潜力。COMMA可用于详细研究岩浆混合的时空发展，提供有关这一基本岩石学和火山学过程的信息，而这一过程通过直接观测是无法研究的。这种新实验装置的潜力之一是建立经验关系，将通过实验时间序列获得的混合时间与熔体之间的化学交换联系起来，以限制火山系统的混合到喷发时间，这是火山灾害评估中的一个基本课题。
