Publicaciones

Structural characteristics of an active fold-and-thrust system in the southeastern Atacama Basin, northern Chile

Investigadores

Gabriel González

Journal

Tectonophysics

Línea de investigación

Amenazas por procesos de tierra sólida

Institución

Universidad Católica del Norte

Disciplina

Ciencias de la Tierra

afiliacion

Yen-Sheng Lin, Department of Geosciences, National Taiwan University, Taipei 106, Taiwan

Yi-Rung Chuang, Department of Geosciences, National Taiwan University, Taipei 106, Taiwan

J. Bruce H. Shyu, Department of Geosciences, National Taiwan University, Taipei 106, Taiwan

Gabriel González, Departamento de Ciencias Geológicas, Universidad Católica del Norte, Antofagasta, Chile. Centro Nacional de Investigación para la Gestion Integrada de Desastres Naturales (CIGIDEN), Chile

Chuan-Chou Shen, Department of Geosciences, National Taiwan University, Taipei 106, Taiwan

Ching-Hua Lo, Department of Geosciences, National Taiwan University, Taipei 106, Taiwan

Ya-Hsuan Liou, Department of Geosciences, National Taiwan University, Taipei 106, Taiwan

Abstract

The western South American margin is one of the most active plate boundaries in the world. Using various remote sensing data sets, we mapped the neotectonic characteristics of an area at the southeastern corner of the Atacama Basin, northern Chile, in the Andean forearc. There, one major N-S trending ridge is clearly visible both in the satellite images and in the field. This ridge reaches 250 m above the basin floor in its middle part and is asymmetrical, with a steep eastern slope and a much gentler western slope. The geometry of the ridge indicates that it formed as an asymmetrical anticline. This anticline is likely formed as a shear fault-bend fold, with a major décollement at a depth of about 2.5 km in the Naranja Formation. We suggest that this décollement is a major structure of the Atacama Basin area. From the ages of the ignimbrites and lake deposits that were deformed by this anticline, we obtained a long-term shortening rate of the major underlying structure at about 0.2 mm/yr. This thin-skinned fold-and-thrust system appears to be active since at least about 3 Ma, and could be as long as since middle Miocene. Therefore, crustal structures may play important roles in the Neogene development of the western Andean margin.

Keywords

Active tectonics, Tectonic geomorphology, Atacama Basin, Andes, Shear fault-bend fold

Link

Ver publicación