Onset of foreland basin deposition in the Neuquén Basin (34°-35°S): New data from sedimentary petrology and U–Pb dating of detrital zircons from the Upper Cretaceous non-marine deposits

Abstract

A multi-proxy provenance approach using sedimentology, petrology and detrital zircon U-Pb geochronology provides new constrains for the evolution of the Southern Central Andes. The Upper Cretaceous non-marine deposits of the Neuquén Basin referred as Neuquén Group in the central and southern sector of the basin, have been characterized as the first foreland basin associated with the early uplift of the Andean orogen at ca. 100 Ma. However, in the northern sector of the basin, the stratigraphically equivalent Diamante Formation has not been studied in detail yet. This work focuses in the outcrops of the Diamante Formation located between Laguna del Diamante and Atuel River in southern Mendoza Province, Argentina (34°-35°S). The petrographic analysis of sandstones shows high content of volcanic and calcareous lithic fragments suggesting provenance from the underlying sedimentary units and the coeval volcanic arc associated with the onset of an important stage of deformation on the west. Detrital zircons from the base of the Diamante Formation were supplied sources from Upper Jurassic and Lower Cretaceous that were exposed during Upper Cretaceous times, whereas in the top, a high content of Permo-Triassic detrital zircons indicates

Cretaceous and Eocene Rapid Cooling Phases in the Southern Andes (36°–37°S): Insights From Low‐Temperature Thermochronology, U‐Pb Geochronology, and Inverse Thermal Modeling From Domuyo Area, Argentina

“…The oldest cooling age and the thermal histories of Choiyoi Group samples reflect and Albian-Campanian cooling episode, lasting since ∼110 to 75 Ma (Table 1, Figures 8a, 8b, and 10c, and stage 1B in Figure 9c). This cooling episode is consistent with: (i) the onset of the Andean orogeny interpreted by provenance studies in the foreland of the Southern Andes between 34°S and 39°S Borghi et al, 2019;Di Giulio et al, 2012Gómez et al, 2019;Tunik et al, 2010) (Figures 2 and 3); (ii) the beginning of exhumation and magmatism in the fore-arc (Glodny et al, 2008;Tapia et al, 2020); and (iii) a major change in plate's configuration and spreading rates at a global scale (Matthews et al, 2012;Müller et al, 2016;Somoza & Zaffarana, 2008). Assuming the geothermal gradient of ∼51 °C/km (Sigismondi, 2013;Sigismondi & Ramos, 2009a, 2009b, the Albian-Campanian rapid cooling event implies maximum cooling rates of 12 ± 4 to 23 ± 10 °C/Ma and exhumation rates of up to ∼0.5 ± 0.2 mm/yr (see Table S4.2 for de- The location of samples is projected onto the profile maintaining their relative elevation.…”

“…The erosive products were transported and deposited eastwards in the Neuquén Group deposits, simultaneous with the development of the Cretaceous foreland basin (Di Giulio et al, 2012Giulio et al, , 2016Mpodozis & Ramos, 1990;Ramos, 1981;Tunik et al, 2010). As previously mentioned, the onset of rapid cooling at 110 Ma (±3 Ma considering the 95% confidence intervals for the average) is consistent with the maximum depositional ages of 109-100 Ma reported for Neuquén Group synorogenic deposits at 35°-38°S (Borghi et al, 2019;Di Giulio et al, 2012Fennell et al, 2015;Gómez et al, 2019;Tunik et al, 2010). Therefore, erosion would have started almost simultaneously with the onset of uplift of Choiyoi Group units, with generation of positive relief and intense denudation.…”

“…The beginning of the crustal shortening along the western South American plate by Late Mesozoic times promoted the deposition of the first continental synorogenic foreland deposits in the Neuquén Basin during the latest Early-Late Cretaceous, which integrate the Neuquén Group (Di Giulio, 2012;Fennell et al, 2015;Gómez et al, 2019;Tunik et al, 2010) (Figures 2 and 4). Conspicuously, thermochronological data from the Chos Malal fold-and-thrust belt (ChMFTB) suggest the onset of cooling and inferred exhumation at ∼72 Ma, long after the initiation of synorogenic sedimentation (Rojas Sánchez et al, 2018Sánchez et al, , 2020Zamora Valcarce et al, 2009) (Figures 2 and 3).…”

“…The relative magnitude and timing of the different tectonic phases responsible for its genesis are still a matter of debate. While the beginning of mountain building at these latitudes is suggested as latest Early to Late Cretaceous times (Di Giulio et al, 2012Fennell et al, 2015;Gómez et al, 2019;Tunik et al, 2010), the oldest low-temperature thermochronological data indicate that the exhumation in the ChMFTB did not take place before ∼72 Ma (Rojas Sánchez et al, 2018Sánchez et al, , 2020Zamora Valcarce et al, 2009). Structural analysis and inverse thermal history modeling of apatite fission track data reveal a Late Cretaceous-Paleogene cooling episode, interpreted as the main compressive phase of the ChMFTB (Rojas .…”

Northward propagation of Andean genesis: Insights from Early Cretaceous synorogenic deposits in the Aysén-Río Mayo basin

“…1a). In this area, timing of foreland basin inception is either interpreted to correspond with the base of the nonmarine Neuquén Group and Diamante Formation (~107-98 Myr) (Groeber, 1946(Groeber, , 1947Ramos, 1981b;Tunik et al, 2010;Di Giulio et al, 2012;Fennell et al, 2017;Balgord and Carrapa, 2016;Gómez et al, 2019) or an the unconformity between the Huitrín Formation and the Rayoso Group (Cobbold and Rossello, 2003;Mosquera and Ramos, 2006), at sometime after 124 Ma and before ~120…”