Abstract Aragats stratovolcano, located on the South Armenian block, a micro-plate in the Arabian-Eurasian collision zone, has a complex and long-lasting Quaternary eruption history. Cataclysmic eruptions formed widespread pyroclastic deposits, which are interrupted by numerous basaltic to trachytic lava flows as well as lacustrine and lacustrine-alluvial sediments. Contrary to previous concepts, detailed mapping of lithofacies variation combined with stratigraphic documentation and new high-precision 40Ar/39Ar ages revealed four eruption cycles, each started with mafic lavas and generally finalized with pyroclastic deposits. These data contributed to a fundamental reinterpretation of the development of the Aragats Volcanic Province (AVP). Within an estimated activity of one million years, Aragats itself experienced three eruption stages, two of which culminated in pyroclastic deposits of remarkable lithofacies variability with ages of 0.97 to 0.90 Ma and 0.75 to 0.65 Ma, respectively. Vertical and lateral changes in proximal and distal facies distribution of pyroclastic flow deposits indicate temporal variations in eruption intensity and periods of relative volcanic quiescence. Aragats' explosive activities were dominated by Plinian eruptions with columns as high as 25 km, while others are characterized by low eruption columns followed by instantaneous collapse, in one case associated with vent widening, possible caldera collapse and breccia formation. Furthermore, one AVP unit features juvenile lapilli and blocks including banded and armored pumice, indicating magma mingling and their involvement in the erupting mixture before magma fragmentation.

中文翻译：

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Aragats 层状火山（小高加索）第四纪环平原和山谷围成的火山碎屑沉积物：岩相、地质年代学和喷发历史

摘要 Aragats 成层火山位于亚美尼亚南部地块，是阿拉伯-欧亚碰撞带的微板块，具有复杂而持久的第四纪喷发历史。剧烈的喷发形成了广泛的火山碎屑沉积物，这些沉积物被大量玄武岩至粗质熔岩流以及湖相和湖相冲积沉积物打断。与之前的概念相反，岩相变化的详细绘图结合地层记录和新的高精度 40Ar/39Ar 年龄揭示了四个喷发周期，每个周期都从基性熔岩开始，通常以火山碎屑沉积物结束。这些数据有助于从根本上重新解释阿拉加特火山省 (AVP) 的发展。在估计的一百万年的活动中，阿拉加特本身经历了三个喷发阶段，其中两个最终形成岩相变化显着的火山碎屑沉积物，年龄分别为 0.97 至 0.90 Ma 和 0.75 至 0.65 Ma。火山碎屑流沉积物近端和远端相分布的垂直和横向变化表明喷发强度和相对火山静止期的时间变化。Aragats 的爆炸活动主要是 Plinian 喷发，柱高高达 25 公里，而其他喷发的特点是低喷发柱，然后是瞬间坍塌，其中一种与喷口扩大、可能的火山口坍塌和角砾岩形成有关。此外，一个 AVP 单元具有幼年火山岩和块体，包括带状和带状浮石，表明岩浆混合以及它们在岩浆破碎之前参与喷发的混合物。