The internal versus external dynamics in building the Andes (46°30′–47°30′ S) at the Patagonia slab window, with special references to the lower Miocene morphotectonic frontline: a review

New fieldwork and tectonic analysis has been carried out along the Andean morphotectonic frontline between 46°30’ 47°30′S. The right lateral transtensional Marques–Zeballos Pass fault system (MZPRS) controlled 800–1200 m uplift of Andes at 16.1–18.1 Ma. Our data indicate that there was no lower Miocene contractile event frontline. Main Thrust (MAT), which is deeply rooted in upper crust a retroarc thrust dipping 10–15° westward, provides evidence for major crustal shortening ~120 At time arc volcanic strata Ibañez Fm (148–178 Ma) transported eastward above rift Quemado (144179 Ma), lies unconformably on Deseado basement massif. geologic records from together with available allow us to identify processes controlling dynamic evolution two main topographic features studied segment. (1) Upward convection originating subducted South Chile Ridge −1 segment (SCR −1) dynamically sustaining high topography North Patagonian Icefield (4070 Mt. San Valentin, ~2 km higher than Southern Volcanic Zone). This, locus maximum moisture being 47°S during glacial events resulted producing largest lobes Patagonia. (2) 180 long, E–W trending antiformal arch structure Zeballos (MZR, hinge zone N–S MZPRS) straddling Foreland proposed be morphological “twin” American Plate Moho Plateau (SAM MOHO P). SAM P controls location both MZPRS MZR boundaries through time. Patagonia Slab Window asthenospheric dynamics (upward corner flows, respectively) their in–depth interaction appear control whole powerful feedback loop tectonics, morphology, climate, least past 3–4 Myr.