The Arequipa Massif of Peru: new SHRIMP and isotope constraints on a Paleoproterozoic inlier in the Grenvillian orogen

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...

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Detalles Bibliográficos
Autores principales: Casquet, C., Fanning, C., Galindo, C., Pankhurst, R. J., Rapela, Carlos Washington, Torres, P.
Formato: Articulo Preprint
Lenguaje:Inglés
Publicado: 2010
Materias:
Geología
Arequipa Massif
Grenvillian orogeny
Paleoproterozoic
U–Pb SHRIMP zircon dating
Rodinia
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/128709
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-128709
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Geología
Arequipa Massif
Grenvillian orogeny
Paleoproterozoic
U–Pb SHRIMP zircon dating
Rodinia
spellingShingle Geología
Arequipa Massif
Grenvillian orogeny
Paleoproterozoic
U–Pb SHRIMP zircon dating
Rodinia
Casquet, C.
Fanning, C.
Galindo, C.
Pankhurst, R. J.
Rapela, Carlos Washington
Torres, P.
The Arequipa Massif of Peru: new SHRIMP and isotope constraints on a Paleoproterozoic inlier in the Grenvillian orogen
topic_facet Geología
Arequipa Massif
Grenvillian orogeny
Paleoproterozoic
U–Pb SHRIMP zircon dating
Rodinia
description 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 Camana areas and in the San Juan 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.
format Articulo
Preprint
author Casquet, C.
Fanning, C.
Galindo, C.
Pankhurst, R. J.
Rapela, Carlos Washington
Torres, P.
author_facet Casquet, C.
Fanning, C.
Galindo, C.
Pankhurst, R. J.
Rapela, Carlos Washington
Torres, P.
author_sort Casquet, C.
title The Arequipa Massif of Peru: new SHRIMP and isotope constraints on a Paleoproterozoic inlier in the Grenvillian orogen
title_short The Arequipa Massif of Peru: new SHRIMP and isotope constraints on a Paleoproterozoic inlier in the Grenvillian orogen
title_full The Arequipa Massif of Peru: new SHRIMP and isotope constraints on a Paleoproterozoic inlier in the Grenvillian orogen
title_fullStr The Arequipa Massif of Peru: new SHRIMP and isotope constraints on a Paleoproterozoic inlier in the Grenvillian orogen
title_full_unstemmed The Arequipa Massif of Peru: new SHRIMP and isotope constraints on a Paleoproterozoic inlier in the Grenvillian orogen
title_sort arequipa massif of peru: new shrimp and isotope constraints on a paleoproterozoic inlier in the grenvillian orogen
publishDate 2010
url http://sedici.unlp.edu.ar/handle/10915/128709
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