Northward propagation of Andean genesis: Insights from Early Cretaceous synorogenic deposits in the Aysén-Río Mayo basin
| Autor: | Andrés Folguera, Brian K. Horton, Kristina L. Butler, Marianela Díaz, Guido M. Gianni, Alfonso Encinas, Andrés Echaurren, César Navarrete |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Provenance
010504 meteorology & atmospheric sciences Geology Orogeny SYNOROGENIC DEPOSITS Diachronous 010502 geochemistry & geophysics 01 natural sciences Cretaceous Ciencias de la Tierra y relacionadas con el Medio Ambiente purl.org/becyt/ford/1 [https] CRETACEOUS CONTRACTION GROWTH STRATA Paleontology Igneous rock purl.org/becyt/ford/1.5 [https] Geochronology Geología ANDES Sedimentology Structural geology CIENCIAS NATURALES Y EXACTAS 0105 earth and related environmental sciences |
| Zdroj: | CONICET Digital (CONICET) Consejo Nacional de Investigaciones Científicas y Técnicas instacron:CONICET |
| Popis: | Decoding the earliest orogenic stages in the Andes, the largest subduction orogen on Earth is fundamental to understanding changes in climate, drainage organization, and biodiversity in South America. Furthermore, it is crucial to unraveling the driving mechanism behind the initiation of orogeny. To track the earliest stages of Andean growth, we studied the Aysén/Río Mayo basin (ARB) in the North Patagonian Andes. The small degree of Cenozoic tectonic overprinting in this part of the Andes has allowed outstanding preservation of the deformational and sedimentary record of the earliest Andean deformation. In this study, we employ a multidisciplinary approach involving structural geology, sedimentology, geochronology, and provenance studies from the Early Cretaceous Apeleg Formation (~130?122 Ma) in the ARB and geochemical analysis of intrusive Cretaceous igneous rocks. Particularly, the recognition of syncontractional growth strata at several localities indicate a syntectonic origin for this unit and provide additional structural evidence of Early Cretaceous contraction in the North Patagonian Andes. Thus, the Apeleg Formation is interpreted as deposited during a contractional basin stage. Geochemical data from Aptian-Albian intrusive igneous rocks indicate that initial contraction emplaced over thinned crust likely inherited from the Jurassic extension in the ARB. This stage is then compared with a new synthesis of the earliest Cretaceous contraction along the Andes. This analysis reveals that the ARB likely holds the oldest post-Gondwanic synorogenic unit along the orogen and more significantly, that Andean birth was a diachronous process which propagated northward since the late Early Cretaceous. The latter findings have major implications for the evolution of the Andes and shed light into the driving mechanism behind initial orogeny. Fil: Gianni, Guido Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Navarrete Granzotto, César Rodrigo. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Echaurren Gonzalez, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Díaz, Marianela Ximena Yasmin. Universidad Nacional de San Juan; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Butler, Kristina L.. University of Texas at Austin; Estados Unidos Fil: Horton, Brian K.. University of Texas at Austin; Estados Unidos Fil: Encinas, Alfonso. Universidad de Concepción; Chile Fil: Folguera Telichevsky, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina |
| Databáze: | OpenAIRE |
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