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
| Autor: | Jacques Bourgois, Jose Frutos, Maria Eugenia Cisternas |
|---|---|
| Přispěvatelé: | Institut des Sciences de la Terre de Paris (iSTeP), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Instituto de Geologia Economica Aplicada |
| Rok vydání: | 2021 |
| Předmět: |
Slab window
geography geography.geographical_feature_category Rift 010504 meteorology & atmospheric sciences Subduction Andean frontline 15. Life on land Fault (geology) Morphotectonic 010502 geochemistry & geophysics 01 natural sciences Paleontology Tectonics Basement (geology) Uplift dynamics [SDU]Sciences of the Universe [physics] Patagonia South American Plate General Earth and Planetary Sciences Foreland basin Geology Orogenesis 0105 earth and related environmental sciences |
| Zdroj: | Earth-Science Reviews Earth-Science Reviews, Elsevier, 2021, 223, pp.103822. ⟨10.1016/j.earscirev.2021.103822⟩ |
| ISSN: | 0012-8252 |
| DOI: | 10.1016/j.earscirev.2021.103822 |
| Popis: | International audience; New fieldwork and tectonic analysis has been carried out along the Andean morphotectonic frontline between 46°30’ and 47°30′S. The right lateral transtensional Marques–Zeballos Pass fault system (MZPRS) controlled the 800–1200 m uplift of the Andes at 16.1–18.1 Ma. Our data and analysis indicate that there was no lower Miocene contractile event along the Andean morphotectonic frontline. The Main Andean Thrust (MAT), which is deeply rooted in the upper crust is a retroarc thrust dipping 10–15° westward, and provides evidence for major crustal shortening at ~120 Ma. At that time the arc volcanic strata of the Ibañez Fm (148–178 Ma) was transported eastward above the rift volcanic Quemado Fm (144179 Ma), which lies unconformably on the Deseado basement massif.The geologic records from the fieldwork together with the available data allow us to identify the processes controlling the dynamic evolution of the two main topographic features of the studied Andean segment. (1) Upward convection originating from the subducted South Chile Ridge −1 segment (SCR −1) is dynamically sustaining the high topography of the North Patagonian Icefield (4070 m at the Mt. San Valentin, ~2 km higher than the Southern South Volcanic Zone). This, together with the locus of maximum moisture being at 47°S during glacial events has resulted in producing the two largest glacial lobes of Patagonia. (2) The 180 km long, E–W trending antiformal arch structure of the Mt. Zeballos Ridge (MZR, a hinge zone trending N–S along the MZPRS) straddling the Andes and the Foreland is proposed to be the morphological “twin” of the South American Plate Moho Plateau (SAM MOHO P). The SAM MOHO P controls the location of both the MZPRS and the MZR boundaries location through time. The Patagonia Slab Window and SAM asthenospheric dynamics (upward and corner flows, respectively) and their in–depth interaction appear to control the morphotectonic evolution of the whole studied segment through a powerful feedback loop between tectonics, morphology, and climate, at least for the past 3–4 Myr. |
| Databáze: | OpenAIRE |
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