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oai:docta.ucm.es:20.500.14352/418452024-07-19T16:50:05Zcom_20.500.14352_14col_20.500.14352_15
Docta Complutense author Casquet Martín, César author Fanning, C.M. author Galindo Francisco, María Del Carmen author Pankhurst, R.J. author Rapela, Carlos W. author Torres , P. 2023-06-20T00:03:39Z 2023-06-20T00:03:39Z 2010 0895-9811 https://hdl.handle.net/20.500.14352/41845 http://www.elsevier.com/ locate/ jsames The enigmatic Arequipa Massif of southwestern Peru is an outcrop of Andean basement that underwent Grenville-age metamorphism, and as such it is important for the better constraint of Laurentia–Amazonia ties in Rodinia reconstruction models. U–Pb SHRIMP zircon dating has yielded new evidence on the evolution of the Massif between Middle Paleoproterozoic and Early Paleozoic. The oldest rock-forming events occurred in major orogenic events between ca. 1.79 and 2.1 Ga (Orosirian to Rhyacian), involving early magmatism (1.89–2.1 Ga, presumably emplaced through partly Archaean continental crust), sedimentation of a thick sequence of terrigenous sediments, UHT metamorphism at ca. 1.87 Ga, and late felsic magmatism at ca. 1.79 Ga. The Atico sedimentary basin developed in the Late-Mesoproterozoic and detrital zircons were fed from a source area similar to the high-grade Paleoproterozoic basement, but also from an unknown source that provided Mesoproterozoic zircons of 1200–1600 Ma. The Grenville-age metamorphism was of low-P type; it both reworked the Paleoproterozoic rocks and also affected the Atico sedimentary rocks. Metamorphism was diachronous: ca. 1040 Ma in the Quilca and Camaná areas and in the San Juán Marcona domain, 940 ± 6 Ma in the Mollendo area, and between 1000 and 850 Ma in the Atico domain. These metamorphic domains are probably tectonically juxtaposed. Comparison with coeval Grenvillian processes in Laurentia and in southern Amazonia raises the possibility that Grenvillian metamorphism in the Arequipa Massif resulted from extension and not from collision. The Arequipa Massif experienced Ordovician–Silurian magmatism at ca. 465 Ma, including anorthosites formerly considered to be Grenvillian, and high-T metamorphism deep within the magmatic arc. Focused retrogression along shear zones or unconformities took place between 430 and 440 Ma. eng The Arequipa Massif of Peru: New SHRIMP and isotope constraints on a Paleoproterozoic inlier in the Grenvillian orogen journal article URL https://docta.ucm.es/bitstreams/955e2a1c-014b-4067-8e8e-493def345f67/download File MD5 7417ae1c7ff5c94260590048434cc9b4 8963428 application/pdf Casquet_2009.pdf URL https://docta.ucm.es/bitstreams/2a0cadb5-48e7-41ce-81bb-13683f561a72/download File MD5 22433366e53662f4e8c44640c860c6e1 83672 text/plain Casquet_2009.pdf.txt