Normal faulting along the southern margin of the Puna Plateau, northwest Argentina

Abstract

Though orogen‐parallel shortening and vertical extension have dominated the tectonic evolution of the central Andes, a significant kinematic shift from horizontal contraction to extension appears to have occurred within the high Puna‐Altiplano Plateau, with the establishment of extension oblique to the orogen since late Miocene time. We present data from the southern margin of the Puna Plateau, NW Argentina, where new normal faults have been documented in the Fiambalá, Punta Negra, and La Quebrada areas. The unifying characteristics of these areas are that young normal faults reactivate or crosscut older thrust and reverse faults. The relationship between the faults and the late Miocene–Pliocene Punaschotter conglomerate suggests that the extensional faulting must be younger than 3.5 to 7 Ma. Existing data are incomplete but indicate that similar horizontal extension has occurred in many regions throughout the Puna‐Altiplano Plateau, while shortening continues along the plateau margins. Given the spatial and temporal distribution of this late Miocene to Pliocene kinematic shift, both lithospheric loss in the Puna Plateau and plateau‐wide gravitational extensional spreading enhanced by slowing of plate convergence rate could be responsible. The young, disorganized, horizontal extension in the Andes today may be the precursor to more pronounced extension such as observed on the Tibetan Plateau since mid‐Miocene time.

Plio-Quaternary extensional tectonics of the Central Anatolian Plateau: a case study from the Tuz Gölü Basin, Turkey

“…However, the similarity between the average fault displacement rates along the eastern margin of the Tuz Gölü Basin and the average river incision rates could imply that movement along the faults in the Tuz Gölü-Cappadocia region are responsible for the locally observed river incision. The 2 interpretations (regional relative base level fall versus local fault control) may be linked if the normal faulting is also related to the regional-scale plateau uplift, as has been proposed for the high plateaus in Tibet (Armijo et al 1986) and the Altiplano (Schoenbohm & Strecker 2009;Montero Lopez et al 2010). This interpretation further suggests that the lithospheric-scale processes responsible for uplift of the southern plateau margin (Boschi et al 2010;Cosentino et al 2012;Schildgen et al 2012aSchildgen et al , 2012b, which started in the Late Miocene (Cosentino et al 2012;Schildgen et al 2012aSchildgen et al , 2012b, might also be responsible for the evolution of the Tuz Gölü Basin and surrounding regions.…”

Analysis of geomorphic indices in the southern Central Andes (23°–28°S): Evidence for pervasive Quaternary to Recent deformation in the Puna Plateau

“…Quaternary to Recent normal faults have also been documented from the southern Puna (Schoenbohm and Strecker, 2009;Montero-Lopez et al, 2010). In summary, our observations on the landform evolution in the Puna, Eastern Cordillera and Pampean Ranges are in support of…”

“…1b), such as the Acazoque Fault (Marrett et al, 1994) and the Tucuman Transfer Fault (de Urreiztieta et al, 1996). Despite the pervasive presence of structures accomplishing overall crustal shortening in the southern Central Andes, Miocene to Recent horizontal extension of the upper crust is also known from the southern Puna (Schoenbohm and Strecker, 2009;Montero-Lopez et al, 2010;Zhou et al, 2013) and the Eastern Cordillera (Daxberger and Riller, 2015).…”

“…However, compared to dominantly Quaternary faulting inferred from Smf-indices (Fig. 2a, (Schwab and Lippolt, 1976;Marrett et al, 1994), Quebrada del Toro (Coutand et al, 2001), Luracatao Valley (Santimano and Riller, 2012) and Punta Negra (Schoenbohm and Strecker, 2009), the locations of which are indicated in Fig. 2.…”

“…,Strecker et al (2007),Schoenbohm and Strecker (2009),Santimano and Riller (2012),Daxberger and Riller (2014). (b) Diagram showing calculation of mountain front sinuosity (Smf-) index after Bull and McFadden (1977).…”