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DOI	10.1016/j.tecto.2020.228686
	The closure of the Rocas Verdes Basin and early tectono-metamorphic evolution of the Magallanes Fold-and-Thrust Belt, southern Patagonian Andes (52–54°S)
	Muller V.A.P.; Calderón M.; Fosdick J.C.; Ghiglione M.C.; Cury L.F.; Massonne H.-J.; Fanning C.M.; Warren C.J.; Ramírez de Arellano C.; Sternai P.
发表日期	2021
ISSN	00401951
卷号	798
英文摘要	The Western Domain of the Magallanes Fold-and-Thrust Belt (MFTB) between 52°-54°S is part of a poorly studied hinterland region of the southernmost Andean Cordillera. This domain consists of NNW-SSE trending tectonic slices of pre-Jurassic basement units and Upper Jurassic-Lower Cretaceous ophiolitic complexes and volcano-sedimentary successions of the Rocas Verdes Basin (RVB). New detrital zircon U–Pb ages of metatuffs and metapsammopelites constrain episodes of Late Jurassic rift-related volcanism (ca. 160 Ma) followed by Early Cretaceous sedimentation (ca. 125 Ma) during the opening of the RVB. Shear bands developed in the RVB units further record the initial phases of the Andean Orogeny. The 30-km wide thrust stack located on top of the Eastern Tobífera Thrust consists of mylonitic metatuffs, metapelites and metabasalts with a NE-verging brittle-ductile S1* foliation. Phengite-bearing metatuffs commonly record pressure-temperature (P-T) conditions between ~3–6 kbar and ~210–460 °C, consistent with underthrusting of the RVB beneath the parautochthonous magmatic arc in the west. Peak metamorphic conditions of ~6 kbar and 460 °C are derived from a metapsammopelite with textures of contact metamorphism overprinting early mylonitic structures (at least S1*). A back-arc quartz-diorite, intruded at ca. 83 Na, is in contact with the metapsammopelite and constrain the minimum age of deformation at deep crustal depths. Campanian-Maastrichtian (ca. 70–73 Ma) 40Ar/39Ar phengite dates from a mylonitic metapelite indicate the timing of thrusting and backthrusting during the initial uplift of the underthrusted crustal stack. These findings reveal a ~400 km along-strike connection of mylonite belts in a continent-verging thrust structure that became active at the onset of the Andean orogeny during the closure of the Rocas Verdes back-arc marginal basin. © 2020 Elsevier B.V.
关键词	Fold-and-thrust belt Patagonian Andes Rocas Verdes Basin Shear zones
英文关键词	Textures; Zircon; Contact metamorphism; Detrital zircon; Early Cretaceous; Fold-and-thrust belts; Lower Cretaceous; Metamorphic conditions; Metamorphic evolution; Thrust structures; Silicate minerals; basement rock; brittle deformation; ductile deformation; fold and thrust belt; ophiolite; petrogenesis; petrology; shear zone; Andes
语种	英语
来源期刊	Tectonophysics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/208036
作者单位	Lamir Institute, Earth Science Sector - Geology Department, Universidade Federal do Paraná, Av. Cel. Francisco H. dos Santos 210, Curitiba, Brazil; Dipartimento di Scienze dell'Ambiente e della Terra, Università degli Studi di Milano-Bicocca, Piazza della Scienza 4, Milan, Italy; Carrera de Geología, Facultad de Ingeniería, Universidad Andres Bello, Sazié 2119, Santiago, Chile; Department of Geosciences, University of Connecticut, 354 Mansfield Road, Storrs, CT 06269, United States; Instituto de Estudios Andinos “Don Pablo Groeber”, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina; School of Earth Sciences, China University of Geosciences, Lumo Road 388, Wuhan, 430074, China; Fakultät Chemie, Universität Stuttgart, Pfaffenwaldring 55, Stuttgart, D-70174, Germany; Research School of Earth Sciences, Australian National University, Canberra, Australia; School of Environment, Earth & Ecosystem Sciences, The Open University, Milton Keynes, MK7 6AA, United Kingdom
推荐引用方式 GB/T 7714	Muller V.A.P.,Calderón M.,Fosdick J.C.,等. The closure of the Rocas Verdes Basin and early tectono-metamorphic evolution of the Magallanes Fold-and-Thrust Belt, southern Patagonian Andes (52–54°S)[J],2021,798.
APA	Muller V.A.P..,Calderón M..,Fosdick J.C..,Ghiglione M.C..,Cury L.F..,...&Sternai P..(2021).The closure of the Rocas Verdes Basin and early tectono-metamorphic evolution of the Magallanes Fold-and-Thrust Belt, southern Patagonian Andes (52–54°S).Tectonophysics,798.
MLA	Muller V.A.P.,et al."The closure of the Rocas Verdes Basin and early tectono-metamorphic evolution of the Magallanes Fold-and-Thrust Belt, southern Patagonian Andes (52–54°S)".Tectonophysics 798(2021).