UNIGE document Doctoral Thesis
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Title

Reconstructing north-western Gondwana with implications for the evolution of the Iapetus and Rheic Oceans: a geochronological, thermochronological and geochemical study
Author
Van Der Lelij, Roelant
Directors
Spikings, Richard Alan
Schaltegger, Urs
Defense Thèse de doctorat : Univ. Genève, 2013 - Sc. 4581 - 2013/05/27
Collection Terre et Environnement; 121
Abstract This thesis investigates the tectonic histories of igneous and metamorphic rocks exposed in the Mérida Andes, Venezuela, and Santander Massif, Colombia from the Late Cambrian to the present day. Zircon U-Pb ages from 52 igneous and metamorphic rocks constrain the main periods of arc magmatism on the north-western corner of Gondwana from ~500 to ~413 Ma and from ~294 Ma to ~196 Ma. Peak Barrovian metamorphic conditions are recorded by anatexis at ~477 Ma and the intrusion of synkinematic granitoids until ~472 Ma. Back-arc extension is recorded at ~453 Ma. High exhumation rates constrained by 40Ar/39Ar and apatite U-Pb data suggest a second orogenic phase at ~250 Ma. Combined isotopic data show that the basement rocks of the studied regions are autochthonous to north-western Gondwana, and that arc magmatism sampled more juvenile sources during extension than during orogenesis. Low temperature thermochronology suggests that the Santander Massif started exhuming at ~40 Ma.
Keywords Tectonics — Geochronology — Thermochronology — Isotope geochemistry — Orogenesis — Venezuela — Colombia — Andes — Precambrian — Palaeozoic — Ordovician — Silurian — Permian — Triassic — Jurassic — Exhumation — Granite — Barrovian metamorphism — Granulite — Gondwana — Mérida — Santander — Fission track — Hf — Crustal growth
Identifiers
URN: urn:nbn:ch:unige-316537
Full text
Thesis (27.1 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 and Geochronology
Project FNS: 200021_129497
Citation
(ISO format) 		VAN DER LELIJ, Roelant. Reconstructing north-western Gondwana with implications for the evolution of the Iapetus and Rheic Oceans: a geochronological, thermochronological and geochemical study. Université de Genève. Thèse, 2013. doi: 10.13097/archive-ouverte/unige:31653 https://archive-ouverte.unige.ch/unige:31653

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Deposited on : 2013-12-04

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