A pull apart volcanic related tertiary basin, an example from the Patagonian Andes

The Loncopué Trough: A Cenozoic basin produced by extension in the southern Central Andes

“…(2008) suggested that those sequences constitute a typical foreland basin associated with the steady uplift of the Andes from Late Cretaceous to Neogene times. On the contrary Spalletti and Dalla Salda (1996), Suárez and Emparán (1995), Jordan et al (2001), Radic et al (2002) and Burns (2002), among others, suggest that those depocenters were part of an intra-arc extensional basin. Most of the evidence favoring each hypothesis was based on sedimentological studies, regional basin studies, supposed progressive unconformities, and analyses of low quality 2D seismic lines.…”

Structure of the North Patagonian thick-skinned fold-and-thrust belt, southern central Andes, Argentina (41°–42°S)

“…As we noted in the introduction, several models have been proposed for the origin of the Ñ irihuau-Collón Curá basin, including a pull-apart basin (Spalletti and Dalla Salda, 1996) and an extensional basin with compressional inversion during the Miocene (Mancini and Serna, 1989;Cazau et al, 1989). Our revision of more than 25 seismic lines between 41830 0 and 42830 0 S (Giacosa and Heredia 2000; Giacosa et al, 2001;Afonso, 2002) has led us to the following conclusions: The lower part of the Ñ irihuau Formation shows seismic features consistent with sedimentation in an extensional regime (in continuity with the extensional features of the Ventana volcanics), but the remainder of the basin fill apparently was deposited during the migration of the orogenic wedge toward the foreland (retroarc foreland basin succession).…”

“…Volcanosedimentary pull-apart basins related to transcurrent and anastomosed fractures (Dalla Salda and Franzese, 1987;Spalletti and Dalla Salda, 1996), 2. Extensional basins linked to a backarc environment and overprinted by thrusting and folding during Late Miocene compressional deformation (Mancini and Serna, 1989), and 3.…”

Tertiary tectonics of the sub-Andean region of the North Patagonian Andes, southern central Andes of Argentina (41–42°30′S)

“…They have been described in terms of a pullapart model (Spalletti and Dalla Salda, 1996), pure crustal extension in the backarc (Mancini and Serna, 1989;Cazau et al, 1989), or synorogenic deposition in a foreland basin related to different eastward migration episodes of the orogenic front (Ramos and Cortés, 1984;Heredia, 1999, 2000). In this context and without suggesting a specific origin, Diraison et al (1998) highlight the lack of synextensional seismic fabrics in the basin.…”