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dc.contributor.advisorKapp, Paul A.en_US
dc.contributor.authorPearson, David Malcolm
dc.creatorPearson, David Malcolmen_US
dc.date.accessioned2012-08-14T21:11:23Z
dc.date.available2012-08-14T21:11:23Z
dc.date.issued2012
dc.identifier.urihttp://hdl.handle.net/10150/238635
dc.description.abstractThe American Cordillera, a major mountain belt spanning>15000 km along the western margins of North and South America, formed as a result of crustal shortening and magmatism during ocean-continent convergence. These mountains were the loci of addition and redistribution of continental crust. The contributions presented here address the style, timing, and kinematics of underthrusting of continental crust in the retroarc of the central Andes as well as the rapid burial and metamorphism of forearc rocks that contributed to magmatism in the Canadian Cordillera. This work involved geological mapping and structural analysis coupled with geo- and thermochronological analysis. In the central Andes, results confirm a southward transition in structural style and magnitude of Cenozoic shortening that coincides with the disappearance of a thick Paleozoic basin that accommodated major Cenozoic shortening. U-Pb and (U-Th)/He results also demonstrate that thrust belt kinematics in northwestern Argentina were greatly influenced by pre-orogenic heterogeneities in Cretaceous rift architecture. Results from western Canada reveal that rapid underthrusting of forearc rocks occurred during Late Cretaceous time, likely associated with an episode of shallow subduction. This event did not result in basement-involved foreland uplifts thought to be a signature of shallow subduction in the western United States and central Argentina. Taken together, this work has the major implication that variations in the pre-orogenic upper crustal architecture strongly influence the behavior of the continental lithosphere during orogenesis, a result that challenges geodynamic models that largely neglect upper plate heterogeneities.
dc.language.isoenen_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.subjectstructureen_US
dc.subjecttectonicsen_US
dc.subjectthermochronologyen_US
dc.subjectthrust belten_US
dc.subjectGeosciencesen_US
dc.subjectcentral Andesen_US
dc.subjectCoast Mountainsen_US
dc.titleKinematic History of the Northwestern Argentine Thrust Belt and Late Cretaceous Tectonic Underplating Beneath the Canadian Cordilleraen_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.contributor.committeememberDucea, Mihai N.en_US
dc.contributor.committeememberReiners, Peter W.en_US
dc.contributor.committeememberBennett, Richard A.en_US
dc.contributor.committeememberKapp, Paul A.en_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineGeosciencesen_US
thesis.degree.namePh.D.en_US
refterms.dateFOA2018-08-26T18:44:38Z
html.description.abstractThe American Cordillera, a major mountain belt spanning>15000 km along the western margins of North and South America, formed as a result of crustal shortening and magmatism during ocean-continent convergence. These mountains were the loci of addition and redistribution of continental crust. The contributions presented here address the style, timing, and kinematics of underthrusting of continental crust in the retroarc of the central Andes as well as the rapid burial and metamorphism of forearc rocks that contributed to magmatism in the Canadian Cordillera. This work involved geological mapping and structural analysis coupled with geo- and thermochronological analysis. In the central Andes, results confirm a southward transition in structural style and magnitude of Cenozoic shortening that coincides with the disappearance of a thick Paleozoic basin that accommodated major Cenozoic shortening. U-Pb and (U-Th)/He results also demonstrate that thrust belt kinematics in northwestern Argentina were greatly influenced by pre-orogenic heterogeneities in Cretaceous rift architecture. Results from western Canada reveal that rapid underthrusting of forearc rocks occurred during Late Cretaceous time, likely associated with an episode of shallow subduction. This event did not result in basement-involved foreland uplifts thought to be a signature of shallow subduction in the western United States and central Argentina. Taken together, this work has the major implication that variations in the pre-orogenic upper crustal architecture strongly influence the behavior of the continental lithosphere during orogenesis, a result that challenges geodynamic models that largely neglect upper plate heterogeneities.


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