Abstract We analyze the age distribution provided by 113 sanidine crystals separated from six samples of pyroclastic products of the Bolsena-Orvieto phase of activity at the Vulsini Volcanic District, which were dated via the 40Ar/39Ar single crystal, total fusion method in a previous study. Moreover, we investigate the compositional and depositional features of the dated products, both at the outcrop scale and at the optical microscope, aimed at discriminating the juvenile vs. antecrystic vs. xenocrystic origin of the dated crystals. Results of this study provide insights on the magmatic process preceding the eruptions, as well as on the eruptive mechanisms of the primary deposits. The data also provide a geochronologic context to the history of eruptive activity of the Vulsini Volcanic District, from 590 to 250 ka with greater detail than previously outlined by direct dating of several primary units. Indeed, most of the six samples analyzed in the present work yielded 19 distinct crystal population ages, 10 of which match those of previously dated eruptive units and the other 9 possibly corresponding to primary deposits so far undated.

中文翻译：

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来自火山碎屑沉积物的 40Ar/39Ar 单晶日期提供了 Vulsini 火山区（意大利中部）590-240 ka 喷发期的详细记录

摘要 我们分析了从 Vulsini 火山区 Bolsena-Orvieto 活动阶段的 6 个火山碎屑产物样品中分离出的 113 颗砂质晶体提供的年龄分布，这些样品在先前的研究中通过 40Ar/39Ar 单晶全聚变法测年。 . 此外，我们在露头尺度和光学显微镜下研究了过时产品的成分和沉积特征，旨在区分过时晶体的幼年与前晶与异晶来源。这项研究的结果提供了对喷发前岩浆过程以及原生矿床喷发机制的见解。这些数据还为 Vulsini 火山区的喷发活动历史提供了地质年代背景，从 590 到 250 ka，比以前通过几个主要单位的直接测年所概述的更详细。事实上，在目前的工作中分析的六个样本中的大多数产生了 19 个不同的晶体种群年龄，其中 10 个与先前确定的喷发单元的年龄相匹配，而其他 9 个可能对应于迄今为止未确定年代的原始沉积物。