Terranes and tectonic evolution of the Andes: A regional synthesis.

Persistent Link:
http://hdl.handle.net/10150/187114
Title:
Terranes and tectonic evolution of the Andes: A regional synthesis.
Author:
Richards, David Ronald.
Issue Date:
1995
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The Pacific margin of South America was predominantly a subduction margin throughout the Mesozoic and Cenozoic. In the mid-Cretaceous, the continental margin arc from southernmost South America to southern Peru changed from a near sea-level, "neutral" arc to a subaerial, compressive arc. Only minor terrane accretion occurred in the central and southern Andes during this subduction episode (Darwinia and Canta terranes), but there was extensive Cretaceous-Tertiary accretion of oceanic terranes in the northern Andes (Villa de Cura, Cordillera de la Costa, Amaime, Cauca-Macuchi, Pinon, and Baudo terranes). These oceanic additions to the continent were primarily by an oblique subduction/strike-slip process. The development of an uplifted continental margin arc in the Eocene, shedding coarse sediments to the east, followed the accretion of the Cretaceous oceanic terranes in the northern Andes. The Paleozoic tectonic evolution of the Andean margin, in contrast to the Mesozoic-Cenozoic subduction-dominated evolution, shows a tectonically varied margin in space and time. In the central to southern Andes, lower Paleozoic continental margin terranes (Puna and Precordillera terranes) accreted against a margin that displays lower Paleozoic magmatic arc, as well as rift assemblages. Outboard of these terranes are continental terranes (Arequipa and Chilenia terranes) characterized by Precambrian or lower Paleozoic basement that were in place by the Carboniferous. In the late Paleozoic, subduction complexes (Chiloe and Magallanes terranes) were accreted during development of the late Carboniferous continental margin arc in the southern Andes. In the northern Andes, terranes of continental character were also emplaced (Zamora, Eastern Cordillera and Merida terranes) inboard of the younger oceanic terranes, but their final accretion was a result of the late Paleozoic collision of Gondwana and Laurentia. Late Ordovician and Devonian-Early Carboniferous orogenies affected substantial parts of the Andean margin. A magmatic arc developed along the southern Andes following these orogenies, and it continued into the Mesozoic-Cenozoic without major interruption. A Mesozoic-Cenozoic arc eventually extended the length of western South America, with the subduction process producing the present Andean Cordillera, primarily as a result of Neogene orogeny.
Type:
text; Dissertation-Reproduction (electronic)
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Geosciences; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Coney, Peter J.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleTerranes and tectonic evolution of the Andes: A regional synthesis.en_US
dc.creatorRichards, David Ronald.en_US
dc.contributor.authorRichards, David Ronald.en_US
dc.date.issued1995en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe Pacific margin of South America was predominantly a subduction margin throughout the Mesozoic and Cenozoic. In the mid-Cretaceous, the continental margin arc from southernmost South America to southern Peru changed from a near sea-level, "neutral" arc to a subaerial, compressive arc. Only minor terrane accretion occurred in the central and southern Andes during this subduction episode (Darwinia and Canta terranes), but there was extensive Cretaceous-Tertiary accretion of oceanic terranes in the northern Andes (Villa de Cura, Cordillera de la Costa, Amaime, Cauca-Macuchi, Pinon, and Baudo terranes). These oceanic additions to the continent were primarily by an oblique subduction/strike-slip process. The development of an uplifted continental margin arc in the Eocene, shedding coarse sediments to the east, followed the accretion of the Cretaceous oceanic terranes in the northern Andes. The Paleozoic tectonic evolution of the Andean margin, in contrast to the Mesozoic-Cenozoic subduction-dominated evolution, shows a tectonically varied margin in space and time. In the central to southern Andes, lower Paleozoic continental margin terranes (Puna and Precordillera terranes) accreted against a margin that displays lower Paleozoic magmatic arc, as well as rift assemblages. Outboard of these terranes are continental terranes (Arequipa and Chilenia terranes) characterized by Precambrian or lower Paleozoic basement that were in place by the Carboniferous. In the late Paleozoic, subduction complexes (Chiloe and Magallanes terranes) were accreted during development of the late Carboniferous continental margin arc in the southern Andes. In the northern Andes, terranes of continental character were also emplaced (Zamora, Eastern Cordillera and Merida terranes) inboard of the younger oceanic terranes, but their final accretion was a result of the late Paleozoic collision of Gondwana and Laurentia. Late Ordovician and Devonian-Early Carboniferous orogenies affected substantial parts of the Andean margin. A magmatic arc developed along the southern Andes following these orogenies, and it continued into the Mesozoic-Cenozoic without major interruption. A Mesozoic-Cenozoic arc eventually extended the length of western South America, with the subduction process producing the present Andean Cordillera, primarily as a result of Neogene orogeny.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGeosciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairConey, Peter J.en_US
dc.contributor.committeememberButler, Robert F.en_US
dc.contributor.committeememberChase, Clement G.en_US
dc.contributor.committeememberWallace, Terry C.en_US
dc.identifier.proquest9531132en_US
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