Andean tectonics related to geometry of subducted Nazca plate

Comment on “The West Andean Thrust, the San Ramón Fault, and the seismic hazard for Santiago, Chile” by Rolando Armijo et al.

“…This is in agreement with the dominant vergence of Andean structures and the well-established eastward propagation of deformation [James, 1971;Allmendinger et al, 1983Allmendinger et al, , 1990Jordan et al, 1983Jordan et al, , 1993Ramos 1988Ramos , 2009Mpodozis and Ramos, 1989;Kley et al, 1999;Cristallini and Ramos, 2000;Giambiagi et al, 2001Giambiagi et al, , 2003Coutand et al, 2001;ANCORP Working Group, 2003;Ramos et al, 2004;Kay et al, 2005;Oncken et al, 2006].…”

Paleoenvironmental Model for the Late Cenozoic of Southwestern Amazonia: Paleontology and Geology

“…The Diaguita Upper Pliocene tectonic phase of the Andes (DUMONT et al, 1989;JORDAN et al, 1983) created the present watershed of the Ucayali and fluvial basins of Southwestern Amazonia. Thus, tectonic phase was responsible for the termination of the deposition of the Amazonia megafan system.…”

“…This tectonic phase was initiated in the Bolivian and Pemvian Andes approximatelly 10 ± 2 millions years ago (data review in JORDAN et al, 1983).…”

Tectonics, Climate, and Landscape Evolution of the Southern Central Andes: the Argentine Puna Plateau and Adjacent Regions between 22 and 30°S

“…The Sierras Pampeanas between 27 and 33°S are structurally transitional to the mountain ranges of the Puna and the Cordillera Oriental and comprise Laramide-style crystalline basement uplifts in a region, which coincides with the flat subduction of the oceanic Nazca Plate (e.g., Mon 1979;Jordan et al 1983;Gonzáles and Mon 1996) that became active in late Miocene time after the last Tertiary transgression into the Andean foreland (e.g., Ramos and Alonso 1995;Ramos et al 2002), accelerated after about 4 Ma, and culminated after 3 Ma, when intramontane basin deposits were folded and partly overthrust Bossi et al 2001;Kleinert and Strecker 2001;.…”

“…Contraction in the region of the present-day plateau and adjacent areas in the Eastern Cordillera and the northern Sierras Pampeanas has apparently contributed to the formation of closed depocenters on the present plateau and transiently closed intramontane basins within the other tectonic provinces of northwestern Argentina Alonso et al 1991;Grier et al 1991;Kraemer et al 1999;Coutand et al 2001;Marrett and Strecker 2000;Bossi et al 2001;Carrapa et al 2005). Jordan et al (1983) The Eastern Cordillera comprises a region of late Proterozoic to early Paleozoic metasedimentary and intrusive rocks (e.g., Jezek et al 1985;Omarini 1983) that were uplifted along bivergent, north-northeast striking thrust faults, which were largely responsible for the deformation of Neogene intramontane and foreland sedimentary sequences (Mon and Salfity 1995). In the northern and central portion of this area east of the Cordillera Oriental, the Santa Barbara thrust belt involves Precambrian metagreywackes and Cretaceous and Tertiary sediments.…”