The development of sector zoning in clinopyroxene is attributed to the influence of crystallisation kinetics imposed by magma undercooling () and may reflect variations in magma cooling histories. Yet, the degree of compositional variations between sectors has not been explored as a potential recorder of crystallisation dynamics. Here, we investigate the distribution of major, minor, and trace elements between hourglass {−111} and prism { 0} sectors in clinopyroxene with distinct pre-eruptive histories at Mt. Etna, Italy. We analyse sector-zoned clinopyroxene crystals ranging in size from sub-mm to cm (i.e., microphenocrysts, phenocrysts, and megacrysts), from eruptions fed by the central conduits of the volcano (1669 and 2002–03 flank eruptions) and eruptions fed by eccentric dykes which bypass the central conduits, tapping deeper magma storage regions (1974 and 2002–03 flank eruptions). We focus on Cr-rich mantle zones, which crystallised upon eruption triggering mafic rejuvenation and are ubiquitous across our sample set. With decreasing crystal size (i.e., increasing tetrahedral aluminium is more strongly partitioned between prism and hourglass sectors. This promotes the uptake of rare earth elements (REE) and high field strength elements (HFSE) into prism relative to hourglass sectors. Combining relative degrees of sector enrichment with estimates, we propose magma recharge, mush remobilisation and the onset of magma ascent imposed slightly higher in 1974 than in 2002–03 eruptions at Mt. Etna. Enhanced in 1974 could be related to vigorous mixing and rapid transport of magma with limited storage, resulting in crystals of smaller sizes. Crystal size populations vary across eruptions, but crystals within a given population (e.g., phenocrysts) return similar calculated and REE + HFSE sector enrichments, implying connectivity between magmatic environments in the mush system. We show that the magnitude of sector zoning in clinopyroxene can be employed to explore subtle differences in pre-eruptive dynamics in volcanic systems. As an example, we explore sector enrichment in clinopyroxene phenocrysts from the 2021 eruption at La Palma (Canary Islands) and megacrysts from Roman era activity at Stromboli (Italy). Results highlight the role of dynamic mixing and mush remobilisation before eruption in mafic alkaline settings and suggest changes in magma composition across alkaline systems influence clinopyroxene chemistry but do not influence sector enrichment.

中文翻译：

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单斜辉石扇区分带程度记录动态岩浆补给和上升


单斜辉石扇区带的发展归因于岩浆过冷（）所施加的结晶动力学的影响，并且可能反映了岩浆冷却历史的变化。然而，部门之间的成分差异程度尚未被探索为结晶动力学的潜在记录器。在这里，我们研究了意大利埃特纳火山具有独特喷发前历史的单斜辉石中的沙漏 {−111} 和棱镜 {0} 扇区之间的主要元素、次要元素和微量元素的分布。我们分析了由火山中央管道喷发（1669 年和 2002-03 侧翼喷发）和由火山喷发喷发的扇区单斜辉石晶体，尺寸从亚毫米到厘米（即微斑晶、斑晶和巨型晶体）。偏心堤坝绕过中央管道，利用更深的岩浆储存区域（1974年和2002年3月的侧翼喷发）。我们重点关注富含铬的地幔区域，这些区域在喷发时结晶，引发镁铁质再生，并且在我们的样本集中无处不在。随着晶体尺寸的减小（即，增加的四面体铝在棱镜和沙漏扇形之间的分配更加强烈。相对于沙漏扇形，这促进了稀土元素（REE）和高场强元素（HFSE）进入棱镜中的吸收。结合根据估计，我们认为 1974 年的岩浆补给、糊状再流动和岩浆上升的发生时间略高于 2002 年 3 月埃特纳火山喷发，1974 年的增强可能与岩浆的剧烈混合和快速输送有关。储存，导致较小尺寸的晶体 晶体尺寸群体因喷发而异，但给定群体内的晶体（例如，、斑晶）返回类似的计算值和 REE + HFSE 扇区富集度，这意味着糊状系统中岩浆环境之间的连通性。我们表明，单斜辉石扇区分区的大小可用于探索火山系统喷发前动力学的细微差异。作为一个例子，我们探索了 2021 年拉帕尔马岛（加那利群岛）喷发产生的单斜辉石斑晶和斯特龙博利（意大利）罗马时代活动产生的巨型晶体的扇区富集。结果强调了镁铁质碱性环境中喷发前动态混合和糊状再活化的作用，并表明碱性系统中岩浆成分的变化影响单斜辉石化学，但不影响扇区富集。