Provenance of the Eocene Soebi Blanco formation,Bonaire, Leeward Antilles: Correlations with post-Eocene tectonic evolution of northern South America |
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| Institution: | 1. Department of Earth and Environmental Sciences, University of Geneva, Rue des Maraichers 13, 1205 Geneva, Switzerland;2. Institute of Mineralogy and Geochemistry, University of Lausanne, 1015 Lausanne, Switzerland;3. Instituto Colombiano del Petróleo, Ecopetrol, Bucaramanga, Colombia;1. Instituto de Geociências, Universidade de São Paulo, Rua do Lago 562, CEP 05508-080, São Paulo, SP, Brazil;2. Departamento de Procesos y Energía, Facultad de Minas, Universidad Nacional, Carrera 80 # 65-223, Medellín, Colombia;3. Corporación Geológica Ares, Calle 44A # 53-96, Bogotá, Colombia;4. Department of the Environment, Washington State University, Pullman, Washington 99164, USA;1. GeoZentrum Nordbayern, Friedrich-Alexander-University (FAU) Erlangen-Nürnberg, Schlossgarten 5, 91054 Erlangen, Germany;2. KU Leuven, Department of Earth and Environmental Sciences, Celestijnenlaan 200E, 3001 Leuven, Belgium;3. Servicio Geológico Colombiano, Dirección de Asuntos Nucleares, Carrera 50 N.° 26-20, Bogotá D.C., Colombia |
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| Abstract: | Middle to upper Eocene fluvial strata in the island of Bonaire contain detrital components that were tracked to Precambrian to Triassic massifs in northern Colombia and Venezuela. These detrital components confirm previous hypothesis suggesting that Bonaire and the Leeward Antilles were attached to South American basement massifs (SABM). These are composed of different fragmented South American blocks (Paraguana, Falcon, Maracaibo, Guajira, Perija, and Santa Marta) representing an Eocene, right-laterally displaced tectonic piercing point along the southern Caribbean plate margin. U–Pb LA-ICP-MS from the metamorphic boulders of the Soebi Blanco Formation in Bonaire yield Grenvillian peaks ages (1000–1200 Ma), while detrital zircons recovered from the sandy matrix of the conglomerates contain populations with peaks of 1000 Ma–1200 Ma, 750–950 Ma, and 200–300 Ma. These populations match with geochronological data reported for the northern South American massifs. Thermochronological results from the metamorphic clasts yield Paleocene–middle Eocene ages (65–50 Ma) that confirm a regional-scale cooling event in this time. These data imply a land connection between the SABM and the Leeward Antilles in late Eocene times, followed by a significant strike slip right-lateral displacement and transtensional basin opening starting in latest Eocene times. The succession of Eocene tectonic events recorded by the Soebi Blanco Formation and adjacent basins is a major tracer of the oblique convergence of the Caribbean plate against the South American margin. |
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| Keywords: | Provenance Caribbean plate Conglomerates Leeward Antilles Paleogeography |
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