NEOTECTONIC ANALYSIS IN THE EASTERN PIEDMONT OF FRONTAL CORDILLERA CENTRAL ANDES SAN JUAN ARGENTINA

Documento

Anexos

Metadados

Journal_path

GEOSP

Revista

Geociências (São Paulo)

Volume

36

Número

4

Ano

2017

Data da Publicação

01-12-2017

Palavras-chave

Colangüil Fault System | Morphotectonics | Neotectonics | Piedmont

Title (English)

NEOTECTONIC ANALYSIS IN THE EASTERN PIEDMONT OF FRONTAL CORDILLERA CENTRAL ANDES SAN JUAN ARGENTINA

Abstract (English)

This paper aims to present evidence of neotectonic activity on the eastern piedmont of Cordillera Frontal, Central Andes, Argentina. The geomorphology of the region is complex, resulting of the interaction between sedimentary, climatic and tectonic processes, prevailing in the piedmonts of the main mountain ranges, alluvial fans systems which were deposited during the Pleistocene. The morphology of alluvial systems have been modified by the tectonic activity related to the Colangüil Fault System (CFS) that resulted in anomalies in the drainage network and a set of Quaternary favor-counter slope scarps affecting several alluvial levels. Thus, four alluvial levels were differentiated; being Q1 the most recent and coincident with existing drainage channels and Q4 the oldest, topographically highest and less preserved. Two natural exposures, called in this work Trench I and Trench II, which allowed knowing the kinematics of the faults and the affected deposits, were identified in the southern section of the Colangüil Fault System (SFC). The paleoseismological analysis suggests the occurrence of at least two seismic events in the area, implying that the last event have less than ~37,000 years. Finally, the occurrence of a third event during the Holocene may be not ruled out.

Keywords (English)

Colangüil Fault System | Morphotectonics | Neotectonics | Piedmont

Título (Español)

ANÁLISIS NEOTECTÓNICO EN EL PIEDEMONTE ORIENTAL DE CORDILLERA FRONTAL ANDES CENTRALES SAN JUAN ARGENTINA

Resumen (Español)

El presente trabajo tiene por objetivo dar a conocer evidencias de actividad neotectónica sobre el Piedemonte Oriental de Cordillera Frontal, Andes Centrales, Argentina. La geomorfología de la región es compleja, producto de la interacción entre procesos sedimentarios, climáticos y tectónicos, predominando en los piedemontes de los principales cordones montañosos, sistemas de abanicos aluviales de edad pleistocena. La morfología de los sistemas aluviales ha sido modificada por la actividad tectónica vinculada al Sistema de Fallas Colangüil (SFC), el cual generó durante el Cuaternario, anomalías en la red de drenaje y un conjunto de escarpas a favor y en contra de la pendiente que afectan distintos niveles aluviales. Se diferenciaron 4 niveles aluviales; siendo Q1 el más reciente y coincidente con los actuales cauces y Q4 el más antiguo, el más elevado topográficamente y el menos preservado. En el tramo sur de este sistema se identificaron dos exposiciones naturales, denominadas Trinchera I y Trinchera II que permitieron conocer la cinemática de las fallas y los depósitos afectados. El análisis paleosismológico de las mismas indicaría la ocurrencia en el sector de al menos dos eventos sísmicos, el último de ellos con una edad inferior a ~ 37.000 años. Finalmente no se descarta un tercer evento durante el Holoceno.

Palabras clave (Español)

Morfotectónica | Neotectónica | Piedemonte | Sistema de Fallas Colangüil

Páginas

691-702

Título

NEOTECTONIC ANALYSIS IN THE EASTERN PIEDMONT OF FRONTAL CORDILLERA CENTRAL ANDES SAN JUAN ARGENTINA

Descrição

This paper aims to present evidence of neotectonic activity on the eastern piedmont of Cordillera Frontal, Central Andes, Argentina. The geomorphology of the region is complex, resulting of the interaction between sedimentary, climatic and tectonic processes, prevailing in the piedmonts of the main mountain ranges, alluvial fans systems which were deposited during the Pleistocene. The morphology of alluvial systems have been modified by the tectonic activity related to the Colangüil Fault System (CFS) that resulted in anomalies in the drainage network and a set of Quaternary favor-counter slope scarps affecting several alluvial levels. Thus, four alluvial levels were differentiated; being Q1 the most recent and coincident with existing drainage channels and Q4 the oldest, topographically highest and less preserved. Two natural exposures, called in this work Trench I and Trench II, which allowed knowing the kinematics of the faults and the affected deposits, were identified in the southern section of the Colangüil Fault System (SFC). The paleoseismological analysis suggests the occurrence of at least two seismic events in the area, implying that the last event have less than ~37,000 years. Finally, the occurrence of a third event during the Holocene may be not ruled out.

Autores

JUAN MANUEL ALCACER SANCHEZ | LAURA PATRICIA A. PERUCCA