Crystallisation is a complex process that significantly affects the rheology of magma, and thus the flow dynamics during a volcanic eruption. For example, the evolution of crystal fraction, size and shape has a strong impact on the surface crust formation of a lava flow, and accessing such information is essential for accurate modelling of lava flow dynamics. To investigate the role of crystallisation kinetics on lava flow behaviour, we performed real-time, in situ synchrotron X-ray microtomography, studying the influence of temperature-time paths on the nucleation and growth of clinopyroxene and plagioclase in an oxidised, nominally anhydrous basaltic magma. Crystallisation experiments were performed at atmospheric pressure in air and temperatures from 1250 °C to 1100 °C, using a bespoke high-temperature resistance furnace. Depending on the cooling regime (single step versus continuous), two different crystal phases (either clinopyroxene or plagioclase) were produced, and we quantified their growth from both global and individual 3D texture analyses. The textural evolution of charges suggests that suppression of crystal nucleation is due to changes in the melt composition with increasing undercooling and time. Using existing viscosity models, we inferred the effect of crystals on the viscosity evolution of our crystal-bearing samples to trace changes in rheological behaviour during lava emplacement. We observe that under continuous cooling, both the onsets of the pāhoehoe-‘a‘ā transition and of non-Newtonian behaviour occur within a shorter time frame. With varying both temperature and time, we also either reproduced or approached the clinopyroxene and plagioclase phenocryst abundances and compositions of the Etna lava used as starting material, demonstrating that real-time synchrotron X-ray tomography is an ideal approach to unravel the final solidification history of basaltic lavas. This imaging technology has indeed the potential to provide input into lava flow models and hence our ability to forecast volcanic hazards.

结晶是一个复杂的过程，会显着影响岩浆的流变性，从而影响火山喷发期间的流动动力学。例如，晶体分数、尺寸和形状的演变对熔岩流的表面地壳形成有很大影响，访问这些信息对于熔岩流动力学的准确建模至关重要。为了研究结晶动力学对熔岩流动行为的作用，我们进行了实时、原位同步加速器 X 射线显微断层扫描，研究了温度-时间路径对氧化的名义上无水玄武岩中单斜辉石和斜长石成核和生长的影响岩浆。结晶实验在空气中的大气压和 1250  °C 至 1100 的温度下进行 °C，使用定制的高温电阻炉。取决于冷却方式（单步与连续），产生了两种不同的晶相（单斜辉石或斜长石），我们通过全局和个体 3D 纹理分析量化了它们的生长。电荷的结构演变表明晶体成核的抑制是由于熔体成分随着过冷度和时间的增加而变化。使用现有的粘度模型，我们推断出晶体对含晶体样品的粘度演变的影响，以追踪熔岩侵位过程中流变行为的变化。我们观察到，在持续冷却下，​​pāhoehoe-'a'ā 过渡和非牛顿行为的开始都发生在更短的时间范围内。随着温度和时间的变化，我们还复制或接近了用作起始材料的埃特纳火山熔岩的单斜辉石和斜长石斑晶丰度和成分，证明实时同步加速器 X 射线断层扫描是揭示玄武岩熔岩最终凝固历史的理想方法。这种成像技术确实有可能为熔岩流模型提供输入，因此我们有能力预测火山灾害。