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Title

U-Pb thermochronology, geochronology and geochemistry of NW South America: rift to drift transition, active margin dynamics and implications for the volume balance of continents
Author
Cochrane, Ryan
Directors
Spikings, Richard Alan
Schaltegger, Urs
Defense Thèse de doctorat : Univ. Genève, 2013 - Sc. 4566 - 2013/05/03
Collection Terre et Environnement; 118
Abstract We investigate the Permian – Early Cretaceous (~280 – 113 Ma) tectonic evolution of north-western South America. A new quantitative isotopic and geochemical dataset is presented, which includes, i) 53 U-Pb zircon dates of magmatic rocks and 8 detrital zircon U-Pb age spectra of metasedimentary rocks, ii) 49 weighted mean zircon Hf isotopic analyses of magmatic rocks, iii) 82 whole rock geochemical analyses, including Sr-Pb-Nd isotopic analyses, and iv) apatite U-Pb and 40Ar/39Ar thermochronological data. All of these new data have been acquired from the Eastern Cordillera of Ecuador and the Central Cordillera of Colombia. These data are used to investigate i) the mechanisms and timing of continental fragmentation from back-arc basin extension to the generation of oceanic lithosphere (Chapter 1), ii) the distinction between accretionary and in-situ growth at active continental margins and the implications for the volume balance of continental crust (Chapter 2), and iii) mechanisms of Pb loss in apatite, and the applications of high temperature (~370-570°C) thermochronology for studying the thermal history of the Earth's crust (Chapter 3).
Keywords Continental rifting — Crustal anatexis — Autochthonous — Island arc — Volume diffusion — Inverse-modeling — U-Pb thermochronology
Identifiers
URN: urn:nbn:ch:unige-300297
Full text
Thesis (11.4 MB) - public document Free access
Structures
Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département des sciences de la Terre
Faculté des sciences / Section des sciences de la Terre et de l'Environnement / Département de minéralogie
Research group Isotope Geochemistry, Geochronology and Thermochronology
Project
Swiss National Science Foundation: 200020_134443
Citation
(ISO format) 		COCHRANE, Ryan. U-Pb thermochronology, geochronology and geochemistry of NW South America: rift to drift transition, active margin dynamics and implications for the volume balance of continents. Université de Genève. Thèse, 2013. doi: 10.13097/archive-ouverte/unige:30029 https://archive-ouverte.unige.ch/unige:30029

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Deposited on : 2013-09-30

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