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Neotectonics in the foothills of the southernmost central Andes (37°–38°S): Evidence of strike‐slip displacement along the Antiñir‐Copahue fault zone
Author(s) -
Folguera Andrés,
Ramos Víctor A.,
Hermanns Reginald L.,
Naranjo José
Publication year - 2004
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1029/2003tc001533
Subject(s) - geology , neotectonics , seismology , foreland basin , induced seismicity , foothills , sinistral and dextral , fault (geology) , fault scarp , transform fault , quaternary , strike slip tectonics , paleontology , strain partitioning , thrust fault , cretaceous , tectonics , ecology , biology
The Antiñir‐Copahue fault zone (ACFZ) is the eastern orogenic front of the Andes between 38° and 37°S. It is formed by an east vergent fan of high‐angle dextral transpressive and transtensive faults, which invert a Paleogene intra‐arc rift system in an out of sequence order with respect to the Cretaceous to Miocene fold and thrust belt. 3.1–1.7 Ma volcanic rocks are folded and fractured through this belt, and recent indicators of fault activity in unconsolidated deposits suggest an ongoing deformation. In spite of the absence of substantial shallow seismicity associated with the orogenic front, neotectonic studies show the existence of active faults in the present mountain front. The low shallow seismicity could be linked to the high volumes of retroarc‐derived volcanic rocks erupted through this fault system during Pliocene and Quaternary times. This thermally weakened basement accommodates the strain of the Antiñir‐Copahue fault zone, absorbing the present convergence between the South America and Nazca plates.