Establishing a quantitative link between magmatic processes occurring at depth and volcanic eruption dynamics is essential to forecast the future behaviour of volcanoes, and to correctly interpret monitoring signals at active centres. Chemical zoning in minerals, which captures successive events or states within a magmatic system, can be exploited for such a purpose. However, to develop a quantitative understanding of magmatic systems requires an unbiased, reproducible method for characterising zoned crystals. We use image segmentation on thin section scale chemical maps to segment textural zones in plagioclase phenocrysts. These zones are then correlated throughout a stratigraphic sequence from Saint Kitts (Lesser Antilles), composed of a basal pyroclastic flow deposit and a series of fall deposits. Both segmented phenocrysts and unsegmented matrix plagioclase are chemically decoupled from whole rock geochemical trends, with the latter showing a systematic temporal progression towards less chemically evolved magma (more anorthitic plagioclase). By working on a stratigraphic sequence, it is possible to track the chemical and textural complexity of segmented plagioclase in time, in this case on the order of millennia. In doing so, we find a relationship between the number of crystal populations, deposit thickness and time. Thicker deposits contain a larger number of crystal populations, alongside an overall reduction in this number towards the top of the deposit. Our approach provides quantitative textural parameters for volcanic and plutonic rocks, including the ability to measure the amount of crystal fracturing. In combination with mineral chemistry, these parameters can strengthen the link between petrology and volcanology, paving the way towards a deeper understanding of the magmatic processes controlling eruptive dynamics.

在深度发生的岩浆过程和火山喷发动力学之间建立定量联系对于预测火山的未来行为以及正确解释活动中心的监测信号至关重要。可以利用矿物中的化学分区来实现这一目的，该分区捕获岩浆系统中的连续事件或状态。然而，要对岩浆系统进行定量理解，需要一种无偏见、可重复的方法来表征带状晶体。我们使用薄片尺度化学图上的图像分割来分割斜长石斑晶中的纹理区域。然后，这些区域在圣基茨（小安的列斯群岛）的地层序列中相互关联，由基底火山碎屑流沉积物和一系列秋季沉积物组成。分段斑晶和未分段基质斜长石在化学上与整个岩石的地球化学趋势脱钩，后者显示出向化学演化程度较低的岩浆（更多的钙长石斜长石）的系统时间进展。通过研究地层序列，可以及时跟踪分段斜长石的化学和结构复杂性，在这种情况下大约为数千年。在此过程中，我们发现了晶体种群数量、沉积厚度和时间之间的关系。较厚的矿床包含更多的晶体种群，同时这一数量在矿床顶部总体减少。我们的方法为火山岩和深成岩提供了定量的结构参数，包括测量晶体压裂量的能力。