Lavenu Alain, Cembrano J. (2008). Deformación compresiva cuaternaria en la Cordillera Principal de Chile central (Cajón del Maipo, este de Santiago) = Quaternary compressional deformation in the Main Cordillera of Central Chile (Cajon del Maipo, east of Santiago). Revista Geologica de Chile, 35 (2), p. 233-252. ISSN 0716-0208.
Titre du document
Deformación compresiva cuaternaria en la Cordillera Principal de Chile central (Cajón del Maipo, este de Santiago) = Quaternary compressional deformation in the Main Cordillera of Central Chile (Cajon del Maipo, east of Santiago)
Revista Geologica de Chile, 2008,
35 (2), p. 233-252 ISSN 0716-0208
A detailed study of recent sediments in the Maipo River Valley (Cajon del Maipo), east of Santiago, shows a compressive deformation documented by coeval reverse faults and drag-folds. These structures are characteristic of a principal stress direction trending roughly N-S (N338 degrees E) that also affects the older sediments of the Abanico Formation constituting the bedrock of the Quaternary alluvial terraces. Two deformation episodes are superposed in the bedrock: a Neogene deformation event (post 9 Ma), having an E-W-trending sigma 1, and a late Quaternary event with sigma 1 roughly trending N-S. The latter would be the result of regional-scale partitioning of the oblique convergence vector between the Nazca and South American Plates; a buttress at 33 degrees S would produce a north-south velocity gradient in the forearc leading to regional, north-south shortening. Shallow crustal seismicity in the inner forearc (Main Cordillera) is -at least in part- compatible with the compression direction as obtained from the kinematic analysis of mesoscopic fault-slip data.
