Abstract The aim of this paper is to describe and interpret clastic injectites structures recognized in the eolian deposits of the Tin Tin Member of the Angastaco Formation (Oligocene to Middle Miocene). The Angastaco Formation is part of the Andean foreland basin sedimentation in the Eastern Cordillera of northwestern Argentina. The structures appear in stratal intervals 4.8–8.6 m thick that are interpreted as fluvial-eolian and eolian environments. Clastic injectites are composed of sand pipes that pass upward to inverted cone, and clastic dikes. Synsedimentary faults and bending of laminae, as well as breccias, were observed associated with the clastic injectites. Sand pipes and clastic dikes are tentatively interpreted as the result of liquefaction and fluidization and upward injection of sediment that occurred during active migration of the dune field. Based on 1) vertical repetition of deformed intervals, 2) sedimentary structures comparable to those formed by liquefaction in recent earthquakes, 3) evidence for a shallow water table and for the active tectonism during deposition of the Angastaco Formation, we infer a seismic trigger for the formation of the sand pipes and clastic dikes.

中文翻译：

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阿根廷西北部中新世 Angastaco 组风成沉积物中的砂管作为安第斯变形的记录器

摘要 本文的目的是描述和解释在 Angastaco 组（渐新世至中中新世）锡锡段风成沉积物中识别出的碎屑注入结构。Angastaco 组是阿根廷西北部东科迪勒拉山脉安第斯前陆盆地沉积的一部分。这些结构出现在 4.8-8.6 m 厚的地层间隔中，被解释为河流-风成和风成环境。碎屑注入岩由向上传递到倒锥体的砂管和碎屑岩脉组成。观察到与碎屑注入体相关的同沉积断层和层状弯曲以及角砾岩。沙管和碎屑堤被初步解释为沙丘场活动迁移过程中发生的液化和流化以及沉积物向上注入的结果。基于 1) 变形层段的垂直重复，2) 与最近地震中液化形成的沉积结构相当的沉积结构，3) 浅水位和 Angastaco 地层沉积期间活动构造作用的证据，我们推断出地震触发砂管和碎屑岩脉的形成。