Neogene Patagonian magmatism between the rupture of the Farallon plate and the Chile Ridge subduction

Based on chemical composition and timing of late Paleogene Neogene igneous rocks in southern Patagonia, six suites are identified correlated with subduction processes during the approaching active oceanic ridges. magmatism took place after a period decreased sub-alkaline (LPg Suite). Early Miocene calc-alkaline mark reactivation acceleration (Suite 1). These located at ca. 200 km from trench typical products continental magmatic arcs, where focused metasomatism mantle wedge results high-degree partial melting (>15%) restricted area expressed as narrow volcanic arc. Contrarily, transitional to alkaline 2) were formed Chile spreading ridge hot lithosphere (prior development slab window), encompassed broader region wedge, resulting lower degrees (<15%) wider arc, ca 200–450 trench. Intermediate high Sr/Y ratio 3), either within arc setting, 270 trench, or forearc (less than 20 trench), trailing edge Nazca plate. Alkaline basalts 4) widely distributed, between 220 630 They temporally spatially related window generated Ridge. Andesites 5) Quaternary Austral Volcanic Zone, 160 leading Antarctica The time spatial distribution these allow us propose that diverse Patagonia was controlled by varying thermal structure prior, an ridge. Particularly, variability Suite 2, which is not common other could be used proxy for warm structure.