Geochemistry and tectonic setting of pre-collision Cretaceous and Paleogene volcanic rocks of Ecuador

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Research Article| October 01, 1987 Geochemistry and tectonic setting of pre-collision Cretaceous and Paleogene volcanic rocks of Ecuador M. LEBRAS; M. LEBRAS 1Office de la Recherche Scientifique et Technique Outre-Mer. 24, ruê Bayard, 75008 Paris, France, and Centre Géologique et Geóphysique, Université des Sciences et Techniques du Languedoc, 34060 Montpellier, France Search for other works by this author on: GSW Google Scholar F. MÉGARD; F. MÉGARD 2Centre Géologique et Géophysique, Université des Sciences et Techniques du Languedoc, 34060 Montpellier, France Search for other works by this author on: GSW Google Scholar C. DUPUY; C. DUPUY 2Centre Géologique et Géophysique, Université des Sciences et Techniques du Languedoc, 34060 Montpellier, France Search for other works by this author on: GSW Google Scholar J. DOSTAL J. DOSTAL 3Department of Geology, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada Search for other works by this author on: GSW Google Scholar GSA Bulletin (1987) 99 (4): 569–578. https://doi.org/10.1130/0016-7606(1987)99<569:GATSOP>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation M. LEBRAS, F. MÉGARD, C. DUPUY, J. DOSTAL; Geochemistry and tectonic setting of pre-collision Cretaceous and Paleogene volcanic rocks of Ecuador. GSA Bulletin 1987;; 99 (4): 569–578. doi: https://doi.org/10.1130/0016-7606(1987)99<569:GATSOP>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Pre-collision Cretaceous–lower Tertiary volcanic rocks of western Ecuador from the coastal area (Piñón and San Lorenzo Formations) and Western Cordillera (Macuchi and Celica Formations) consist of three rock suites. The first suite includes tholeiites of ocean-floor affinities that have distinct light REE-depleted patterns and low La/Nb, La/Hf, and Th/Hf ratios. The island-arc tholeiites of the second suite have lower contents of Ti, Zr, Hf, and Nb. The third suite comprises calc-alkalic rocks, mainly continental-margin andesites and dacites. The continental volcanic-arc rocks crop out in an area east of the tholeiitic rocks. The boundary between the two areas is the major suture separating continental South America from accreted terrenes to the west.A model is suggested for the geodynamic evolution of what is now western Ecuador during the Late Cretaceous. It includes two east-dipping subduction zones of Turonian to Santonian ages and the accretion of the oceanic island arc to the continent. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.