Petrogenesis of the Triassic Cuyo basin magmatism: Controls on the magmatic evolution of passive rifts basins in Western Gondwana

Plant Taphonomy in a Lake Affected by Volcanism (Agua De La Zorra Formation, Upper Triassic) Mendoza, Argentina

“…As mentioned before, the Agua de la Zorra taphoflora is represented, as known to date, by plant remains without cuticle preserved (Ottone et al 2011;Pedernera et al 2019). Perhaps the lack of cuticle preserved in the Agua de la Zorra could be due to the fact that basaltic lavas recorded in this unit are classified as alkaline lavas (Ramos and Kay 1991;Ottone et al 2011;Orellano et al 2019). Cuticle preservation has been observed in other depocenters of the Cuyana Basin with volcanic influence such as the Potrerillos and Cacheuta formations, and their chemical structure has been analyzed (D'Angelo et al 2011;D'Angelo and Zodrow 2018;D'Angelo 2019).…”

Gondwanan Inheritance on the Building of the Western Central Andes (Domeyko Range, Chile): Structural and Thermochronological Approach (U‐Pb and40Ar/39Ar)

“…The intraplate origin proposed for the Ischigualasto and Cuyo rift basins (Orellano et al, 2019;Ramos & Kay, 1991) can be thus reconciled into a general model of continuous subduction considering the proximity of the magmatic locus to the subducting slab during the Triassic (Figure 9a). Farther north, alkaline to sub-alkaline basalts and andesites from the Triassic Mitu rift in Perú has been contrastingly interpreted as (1) developed on a continental rift unrelated to subduction (Noble et al, 1978;Spikings et al, 2016), or (2) developed in a back-arc with a hypothesized arc obliterated by Cenozoic tectonic erosion (Reitsma, 2012).…”

“…Interestingly, a similar correlation to the Triassic paleotrench distance is observed in the geochemistry of the Triassic volcanism. Thus, purely intraplate alkaline affinities are recorded in basaltic rocks from the eastern portion of the Ischigualasto basin, (Castro de Machuca et al., 2019) whereas in the western margin of the Cuyo basin, alkaline to subalkaline basalts coexist with calc‐alkaline silicic volcanism (Orellano et al., 2019). The mixed affinity of the Cuyo basin volcanism has been explained as crustal assimilation during an intraplate rifting unrelated to subduction (Orellano et al., 2019).…”

“…Thus, purely intraplate alkaline affinities are recorded in basaltic rocks from the eastern portion of the Ischigualasto basin, (Castro de Machuca et al., 2019) whereas in the western margin of the Cuyo basin, alkaline to subalkaline basalts coexist with calc‐alkaline silicic volcanism (Orellano et al., 2019). The mixed affinity of the Cuyo basin volcanism has been explained as crustal assimilation during an intraplate rifting unrelated to subduction (Orellano et al., 2019). Close to the trench, basaltic to silicic volcanic products from the Domeyko and La Ternera basins have clear calc‐alkaline affinities with trace element compositions typical of volcanic arcs (Oliveros et al., 2020).…”

“…A significant tectonic segmentation has been proposed to explain active subduction conditions in northern Chile and intraplate rifting in Perú during the Triassic (Oliveros et al., 2020). Nonetheless, considering the >300–500 km distance between the arc hypothesized by Reitsma (2012) and the Mitu rift basin and the mixed mantle and volcanic arc affinities observed in the Mitu rift volcanism (Orellano et al., 2019) subtle influence of slab‐derived fluids in the genesis of Mitu magmas cannot be discarded.…”