Fluvial deposits of the Diamante Formation as a record of the Late Cretaceous tectonic activity in the Southern Central Andes, Mendoza, Argentina

Abstract

The Upper Cretaceous nonmarine deposits of the Neuquén Basin have an important regional exposure. These deposits are included in the Neuquén Group, a well-studied unit in both the south and central part of the basin. However, the northernmost exposed between the Laguna del Diamante and the Atuel River-assigned to the Diamante Formation-have not been studied in detail. In the studied area, the Diamante Formation corresponds to a braided fluvial system with moderate sinuosity evolving through time towards an anastomosing fluvial system. Petrographic analyses indicate that sandstones belong to feldspatic litharenites and litharenites, while the source area indicates provenance from both a recycled orogen and a transitional arc. The latter could be linked to the exhumation of the Andean orogen located to the west and to the input from the north-eastern border of the Neuquén Basin, represented by the rocks currently exposed in the San Rafael Block. On a macroscopic scale, the presence of calcareous lithic fragments in the mid and upper part of the surveyed stratigraphic section, strongly suggest an input from the west. This indicates an important change in the polarity of the basin and the presence of a deformation front located to the west of the study area in accordance to previous proposals in equivalent deposits to the south of study area.

Multiproxy provenance analysis of Lower to Upper Cretaceous synorogenic deposits in the Southern Andes (34–35°S): Evidence of coeval volcanism during the onset of the Andean orogeny

“…Between the Early to Late Cretaceous, the Neuquén Basin changed from a backarc extensional basin to a retroarc foreland basin, in response to a westward acceleration of the South American plate during the Cretaceous (Mpodozis and Ramos, 1990;Howell et al, 2005;Ramos and Kay, 2006;Tunik et al, 2010). Congruent with this tectonic setting, several large-scale drainage systems have been interpreted for the Upper Cretaceous non-marine deposits of the Neuquén Basin, based on stratigraphy and sedimentology (e.g., Di Giulio et al, 2012Giulio et al, , 2017Gómez et al, 2019Gómez et al, , 2020. Provenance analyses in the northern part of the basin (34-35°S) suggest that the foreland basin began Umazano et al, 2009;Ghiglione et al, 2015; J o u r n a l P r e -p r o o f Umazano et al, 2009;Ghiglione et al, 2015;Suriano et al, 2017; J o u r n a l P r e -p r o o f Suriano et al, 2017;Bernet, 2019 and references therein) J o u r n a l P r e -p r o o f Bernet, 2019 and references therein)…”

“…1) is a large depocenter developed during Late Triassic to Paleogene times in the southwestern margin of Gondwana ( 30J o u r n a l P r e -p r o o f to Paleogene times in the southwestern margin of Gondwana (30 scale rifting proces J o u r n a l P r e -p r o o f scale rifting processes in response to the break J o u r n a l P r e -p r o o f ses in response to the break supercontinent (Mpodozis and Ramos, 2008;Charrier et al, 2015;D'Elia et al, 2020 J o u r n a l P r e -p r o o f supercontinent (Mpodozis and Ramos, 2008;Charrier et al, 2015;D'Elia et al, 2020 among others), with the potential influence of upper which is temporally equivalent to the youngest formation of the Neuquén Group described south of 35°S (Fig. 1; Gómez et al, 2019Gómez et al, , 2020. A proposed source rock-model includes a westward sediment dispersion derived from the Sierra Pintada System and the San Rafael Block before the uplift of the Andes, which was then shifted eastwards with the onset of the Andean orogeny, associated to a new west-derived source (Tunik et al, 2010;Di Giulio et al, 2012Balgord and Carrapa, 2016;Balgord, 2017;Fennell et al, 2017a, Borghi et al, 2019Gómez et al, 2019Gómez et al, , 2020.…”

“…1; Gómez et al, 2019Gómez et al, , 2020. A proposed source rock-model includes a westward sediment dispersion derived from the Sierra Pintada System and the San Rafael Block before the uplift of the Andes, which was then shifted eastwards with the onset of the Andean orogeny, associated to a new west-derived source (Tunik et al, 2010;Di Giulio et al, 2012Balgord and Carrapa, 2016;Balgord, 2017;Fennell et al, 2017a, Borghi et al, 2019Gómez et al, 2019Gómez et al, , 2020. However, the lack of detailed sedimentological and provenance studies north of 35°S reflects the need for further studies to better understand the tectonic evolution during latest Early to Late Cretaceous times.…”

“…In the last few years, several discrepancies arose regarding the presence of a coeval volcanic arc during the Upper Cretaceous along the western margin of the Neuquén Basin (e.g., Muñoz et al, 2018;Gómez et al, 2019Gómez et al, , 2020. Some authors speculated on a decreasing volcanic activity because of the absence of detrital zircons <100 Ma in the Neuquén Group.…”

Vanadium for Green Energy: Increasing Demand but With Health Implications in Volcanic Terrains

“…Importantly, Westerly winds have supplemented the eroded volcanic sediments with volcanic glass and ash (Mingari et al, 2017). Petrographic studies confirm that the sediment in Argentina and Chile contains volcanic debris derived from the Andes by mechanical erosion (Gómez et al, 2020;Horton, 2018) and volcanic glass. Magnetite grains in the sediment, in which much vanadium may be exported from the Andes, show evidence of alteration (Flint et al, 1986), which would have released the vanadium into groundwaters.…”