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Basement-involved tectonism in the western Central Andes: Insights from the eastern Domeyko and Frontal cordilleras, and the Salar de Atacama Basin
Journal of South American Earth Sciences ( IF 1.8 ) Pub Date : 2022-08-21 , DOI: 10.1016/j.jsames.2022.103981
F. Martínez , M. Peña , C. López

Northern Chile is a natural laboratory to understand the relation between different basement-involved structural styles, mechanisms of basement uplift, and the interaction of Pre-Andean rift-related and Andean contractional structures. Field and geophysical data (two-dimensional seismic profiles) are key to understanding the geometry and kinematics of these structures in the subsurface. Herein, we analyzed the basement-involved tectonism in the easternmost part of the Domeyko Cordillera, the southern end of the Salar de Atacama Basin and the Frontal Cordillera in northern Chile based on an updated revision of the structures exposed on the surface and the other ones present in depth. Our results indicate that the Pre-Andean configuration of the region was the first-order factor controlling the basement-involved deformation. Late Permian to Jurassic rift-related, basement rooted, normal faults accommodated much of the shortening in the upper plate, thus triggering their partial and/or full reverse reactivation, situation that in some places was accompanied by purely reverse faulting, thus allowing the exhumation of large Paleozoic basement granitic blocks. This event occurred in a similar manner in the studied regions from Late Cretaceous to Paleocene in an arc-system geological context. The initial distribution of half-grabens, syn-rift and post-rift sequences governed the variations in the basement-involved structural styles ranging from basement-cored anticlines to tectonic wedges, among others. However, the flat-slab process has frequently been invoked as the main process responsible for the basement-involved tectonism in northern Chile. Our results suggest a strong control exerted by inherited stratigraphic and structural features more than variations in slab geometry.



中文翻译:

中安第斯山脉西部与地下室有关的构造活动:来自东部多梅科和锋线山脉以及阿塔卡马盐沼盆地的见解

智利北部是一个自然实验室,可以了解不同的基底层结构样式、基底层抬升机制以及安第斯前裂谷相关和安第斯收缩结构的相互作用之间的关系。现场和地球物理数据(二维地震剖面)是了解地下这些结构的几何形状和运动学的关键。在此,我们分析了 Domeyko Cordillera 最东部的基底参与构造,Salar de Atacama 盆地的南端和智利北部的 Frontal Cordillera 基于对暴露在表面的结构和其他深度结构的更新修订。我们的研究结果表明,该地区的前安第斯构造是控制基底参与变形的一阶因素。晚二叠世至侏罗纪裂谷相关、基底根系、正断层容纳了上板块的大部分缩短,从而触发了它们的部分和/或全部反向重新激活,在某些地方伴随着纯粹的反向断层,从而允许折返大型古生代基底花岗岩块。这一事件以类似的方式发生在所研究的地区弧系地质背景下的晚白垩世至古新世。半地堑、同裂谷层序和裂谷后层序的初始分布控制着基底所涉及的构造样式的变化,从基底核背斜到构造楔形等。然而,平板过程经常被认为是智利北部涉及基底构造的主要过程。我们的研究结果表明,继承的地层和结构特征比板坯几何形状的变化更能发挥强大的控制作用。

更新日期:2022-08-21
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