4.5 Article

Buried thrust belt front of the western Central Andes of northern Chile: Style, age, and relationship with basement heterogeneities

期刊

JOURNAL OF STRUCTURAL GEOLOGY
卷 147, 期 -, 页码 -

出版社

PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.jsg.2021.104337

关键词

Tectonic inversion; Western central andes; Fold and thrust belt; Orogenic thrust front; Northern Chile

资金

  1. National Research and Development Agency of Chile (ANID)
  2. Fondecyt research project Structure and tectonics of the preAndean Depression, Central Andes: A case of study of the Salar de Punta Negra Basin

向作者/读者索取更多资源

A regional-scale study in northern Chile analyzed the structural characteristics of the thrust belt front of the western Central Andes at 21S using field, seismic, and limited borehole information. The study revealed the presence of blind west-verging inversion anticlines defining the orogenic front of the Central Andes at this latitude, indicating crustal shortening accommodated by vertical motion along the inverted normal faults during tectonic inversion. The results suggest that the thrust belt front in this region is located under the Pampa del Tamarugal, contrary to traditional proposals.
We present a regional-scale study combining field, seismic, and limited borehole information to analyze the structural characteristics of the thrust belt front of the western Central Andes at 21S. This region, located in northern Chile, consists of the easternmost part of the Coastal Cordillera, the Pampa del Tamarugal, and the western Domeyko Cordillera (or Chilean Precordillera). On the surface, a series of N-S-oriented folds alternating between monoclines and narrow anticline and syncline folds containing Mesozoic, Upper Cretaceous, and Cenozoic rocks form part of the main structural styles, which are frequently bound by west-verging reverse faults that form the basement of the deeper structural levels of the upper crust. The interpretation of a regional seismic grid composed of N-S, NE-SW, and WNW-ESE-oriented 2-D seismic profiles revealed the presence of several blind west-verging inversion anticlines that define the orogenic front of the Central Andes at this latitude. These anticline folds are related to the partial and/or total positive reactivation of ancient east-dipping Jurassic normal basement faults bounding half-graben structures and sub-basins developed within the Tarapac ' a Basin. Our results suggest that the thrust belt front in this region is preferably located under the Pampa del Tamarugal, and not along the topographic culmination of the western Precordillera as traditionally proposed. New tectonic restorations of 2-D structural models suggest that, during tectonic inversion, between 3 and 4 km of crustal shortening were accommodated by vertical motion along the inverted normal faults. The presence of Upper Cretaceous synorogenic deposits covering the Jurassic syn-rift deposits on the inversion anticlines indicates that both basin inversion and formation of the western thrust belt front began during the Late Cretaceous, and not during the Eocene Incaic tectonic phase as previously suggested by regional studies developed in the area.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.5
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据