Abstract Monogenetic volcanic fields usually comprise short-lived isolated volcanoes. However, new vents might build over or near to the older ones, resulting in the construction of complex, compound, nested, or overlapping volcanic structures formed by the superposition of individual monogenetic edifices. In the present study, we examine the case of Alchichica Maar volcano that cut through a series of pre-volcanic materials, including sheets of lava flows, pyroclastic deposits, paleosols, and scoria cone deposits. Major and trace elements are used to characterize geochemically each of the different pre-maar and maar units that integrate the Alchichica volcano, allowing to investigate the source composition, syn-eruptive, and crustal magmatic processes and the genetic relationship between the Alchichica maar and the underlying volcanic rocks. Typical lithologies are medium-K calc-alkaline rocks, including basaltic andesites for the lava flow and the scoria cone, and basalts for the maar units and the pre-maar pyroclastic unit. They also present slight variations in La/Sm, Ba/La, Zr/Nb, Ce/Yb, Ce/Pb, and Dy/Yb ratios suggesting different petrological processes such as variable amounts of partial melting in a heterogeneous spinel mantle, fractional crystallization, and crustal contamination during magma ascent. Our results reveal a polymagmatic activity, with different magma batches fed the pre-maar and the maar eruptions. They also allowed depict and confirm a time gap between the eruptive phases of the Alchichica maar formation, which is an add on the polycyclic character of the phreatomagmatic volcanism at this maar and previously described with the volcanostratigraphy examination. In addition, we conclude that the Alchichica maar cannot be defined as a polygenetic volcano; instead, it forms part of a cluster of Late Pleistocene to Holocene overlapped monogenetic volcanoes.

中文翻译：

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Alchichica maar 火山的地球化学特征, Serdán 东方盆地, 东部跨墨西哥火山带: 对单成火山群多岩浆演化的见解

摘要 单生火山场通常由短寿命的孤立火山组成。然而，新的喷口可能会在旧的喷口之上或附近建造，从而导致构建复杂的、复合的、嵌套的或重叠的火山结构，这些结构是由单个单一的建筑物叠加而成的。在本研究中，我们研究了 Alchichica Maar 火山穿过一系列火山前物质的案例，包括熔岩流片、火山碎屑沉积物、古土壤和火山渣锥沉积物。主要元素和微量元素被用来从地球化学上表征整合 Alchichica 火山的每个不同的 pre-maar 和 maar 单元，从而可以研究源组成、协同喷发和地壳岩浆过程以及 Alchichica maar 与火山岩之间的成因关系。下伏火山岩。典型的岩性是中钾钙碱性岩石，包括熔岩流和火山渣锥的玄武质安山岩，以及玛珥单元和前玛尔火山碎屑单元的玄武岩。它们还呈现出 La/Sm、Ba/La、Zr/Nb、Ce/Yb、Ce/Pb 和 Dy/Yb 比率的轻微变化，表明不同的岩石学过程，例如在非均质尖晶石地幔中发生不同数量的部分熔融, 以及岩浆上升过程中的地壳污染。我们的结果揭示了一种多岩浆活动，不同的岩浆批次供给了前马尔和马尔火山喷发。他们还允许描绘和确认 Alchichica maar 地层的喷发阶段之间的时间间隔，这是该 maar 的潜水岩浆火山活动的多环特征的补充，并且之前在火山地层学检查中进行了描述。此外，我们得出结论，Alchichica maar 不能被定义为多基因火山；相反，它是更新世晚期至全新世重叠的单生火山群的一部分。