Geometry and late Mesozoic-Cenozoic evolution of the Salar de Atacama Basin (22°30′-24°30′S) in the northern Central Andes: New constraints from geophysical, geochronological and field data

Effects of pre‐orogenic tectonic structures on the Cenozoic evolution of Andean deformed belts: Evidence from the Salar de Punta Negra Basin in the Central Andes of Northern Chile

“…However, the maximum depositional ages (Upper Cretaceous‐Paleocene) of the syn‐kinematic deposits analysed in this work indicate that the basement deformation started earlier during the boundary between the late Cretaceous‐Paleocene, and may have been diachronous during the Cenozoic until recent times. This support the recent interpretations made by Bascuñan et al (2019), who argued that the contractional deformation in the pre‐Andean Depression started as early as late Cretaceous.…”

“…The new U-Pb detrital zircon ages reported from the syn-kinematic sedimentary rocks of the Pajonales Formation exposed in the footwall block of an east-verging basement reverse fault (see details in Figures 2 and 4) along the northern basin (eastern Sierra de Almeida) and outside of the 2-D seismic coverage, suggest that contractional deformation started at least during the late Cretaceous. These rocks could be correlated with the Upper Cretaceous syn-kinematic Purilactis Formation exposed in the northwest part Salar de Atacama Basin (Bascuñan et al, 2015;Bascuñan et al, 2019) and also with those syn-kinematic seismic reflection packages identified under Paleocene tectonosequences in the central part of the basin (Figure 13; Martínez et al, 2018). Based on this, we suggest that basement faulting within the study area originated between the late-Cretaceous and Paleocene periods ( Figures 12-14).…”

“…We have not found sufficient evidence to suggest that they correspond to fully inverted normal faults. Considering our limited structural and stratigraphic data, we believe that these are only reverse faults that became active after the initial tectonic inversion as recently proposed by Bascuñan et al (2019) and López et al (2019). Previous studies (Martínez et al, 2019; Soto, Martinod, Riquelme, Hérail, & Audin, 2005) found that these faults young and cut the most recent deposits of the basin.…”

Complex Basement‐Involved Contractional Structures in the Pre‐Andean Basins of Northern Chile: A Review From Seismic Data

“…This angular unconformity (see red unconformity in Figure 3) typically marks the transition from an extensional tectonic environment to a compressive one. The volcanic rocks have reported U-Pb ages of 80-70 Ma (Bascuñán et al, 2015(Bascuñán et al, , 2019Henríquez et al, 2018;Martínez et al, 2020; Figure 3) and exhibit important contractional growth strata along syncline folds, thereby recording the first tectonic pulse of Andean orogenesis in the region (Bascuñan, et al, 2019). The rocks are unconformably covered by Paleocene to Eocene (65-45 Ma, Figure 3) sedimentary successions of well-stratified orange and red sandstones intercalated with conglomerate beds (e.g., Arriagada et al, 2006;Dingman, 1963;Mpodozis et al, 2005) exposed along the westernmost part of the Salar de Atacama and Salar de Punta Negra basins (Figure 2b).…”

“…The most common tectonic evolutive models proposed to explain the internal structure of these basins include Late Cretaceous to recent shortening (Arriagada et al, 2006;Bascuñan et al, 2019;López et al, 2019;Martínez et al, 2017;Muñoz et al, 2002), Oligocene to Miocene crustal extension (Flint et al, 1993;T. E. Jordan et al, 2007;Rubilar et al, 2017), and Eocene to early Oligocene transpressional deformation dominated by strike-slip faulting (A. I.…”