<abstract xmlns="http://www.w3.org/1999/xhtml">Evidence of earthquake-induced liquefaction features in the Acequión river valley, central western Argentina, is analysed. Well-preserved soft-sediment deformation structures are present in Late Pleistocene deposits; they include two large slumps and several sand dikes, convolutions, pseudonodules, faults, dish structures and diapirs in the basal part of a shallow-lacustrine succession in the El Acequión River area. The water-saturated state of these sediments favoured deformation.All structures were studied in a natural trench created as a result of erosion by a tributary of the Acequión River, called El Mono Creek. They form part of a large-scale slump system. Two slumps occur in the western portion of the trench and must have moved towards the ENE (70°), where the depocentre of the Boca del Acequión area is situated. Considering the spatial relationship with Quaternary faults, the slumps are interpreted as being due to a seismic event. The thickest dikes in the El Mono Creek trench occur in the eastern portion of the trench, indicating that the responsible earthquake was located to the east of the study area, probably at the Cerro Salinas fault system zone.The slumps, sand dikes and other soft-sediment deformation features are interpreted as having been triggered by earthquakes, thus providing a preliminary palaeoseismic record of the Cerro Salinas fault system and extending the record of moderate-to high-magnitude earthquakes in central western Argentina to the Late Pleistocene.</abstract>

Evidence of earthquake-induced liquefaction features in the Acequión river valley, central western Argentina, is analysed. Well-preserved soft-sediment deformation structures are present in Late Pleistocene deposits; they include two large slumps and several sand dikes, convolutions, pseudonodules, faults, dish structures and diapirs in the basal part of a shallow-lacustrine succession in the El Acequión River area. The water-saturated state of these sediments favoured deformation.All structures were studied in a natural trench created as a result of erosion by a tributary of the Acequión River, called El Mono Creek. They form part of a large-scale slump system. Two slumps occur in the western portion of the trench and must have moved towards the ENE (70°), where the depocentre of the Boca del Acequión area is situated. Considering the spatial relationship with Quaternary faults, the slumps are interpreted as being due to a seismic event. The thickest dikes in the El Mono Creek trench occur in the eastern portion of the trench, indicating that the responsible earthquake was located to the east of the study area, probably at the Cerro Salinas fault system zone.The slumps, sand dikes and other soft-sediment deformation features are interpreted as having been triggered by earthquakes, thus providing a preliminary palaeoseismic record of the Cerro Salinas fault system and extending the record of moderate-to high-magnitude earthquakes in central western Argentina to the Late Pleistocene.

Late Pleistocene-Holocene earthquake-induced slumps and soft-sediment deformation structures in the Acequion River valley, Central Precordillera, Argentina

Consejo Nacional de Investigaciones Científicas y Technicás (CONICET)

Gabinete de Neotectónica. INGEO. Facultad de Ciencias Exactas, Físicas y Naturales. Universidad Nacional de San Juan, Av. Ignacio de La Roza y Meglioli s/n (5400), San Juan, Argentina

Departamento Geología, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de San Juan, Av. Ignacio de La Roza y Meglioli s/n (5400), San Juan, Argentina

Geologos

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Evidence of earthquake-induced liquefaction features in the Acequión river valley, central western Argentina, is analysed. Well-preserved soft-sediment...

Late Pleistocene-Holocene earthquake-induced slumps and soft-sediment deformation structures in the Acequion River valley, Central Precordillera, Argentina

Published Online: Jul 08, 2014

Page range: 147 - 156

Received: Oct 31, 2013

Accepted: Dec 14, 2013

DOI: https://doi.org/10.2478/logos-2014-0007

Keywords
lacustrine sedimentation, liquefaction, seismites, slumps, soft-sediment deformation structures, palaeo-earthquakes

© 2014 Laura P Perucca et. al.

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Late Pleistocene-Holocene earthquake-induced slumps and soft-sediment deformation structures in the Acequion River valley, Central Precordillera, Argentina

Published Online: Jul 08, 2014

Page range: 147 - 156

Received: Oct 31, 2013

Accepted: Dec 14, 2013

DOI: https://doi.org/10.2478/logos-2014-0007

Keywordslacustrine sedimentation, liquefaction, seismites, slumps, soft-sediment deformation structures, palaeo-earthquakes

© 2014 Laura P Perucca et. al.

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
lacustrine sedimentation, liquefaction, seismites, slumps, soft-sediment deformation structures, palaeo-earthquakes