Magmatic evolution of the Andean Eastern Cordillera of Colombia during the Cretaceous: Influence of previous tectonic processes |
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| Authors: | Mónica Vásquez Uwe Altenberger Rolf L Romer Masafumi Sudo Juan Manuel Moreno-Murillo |
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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. Departamento Ciencias de la Tierra, Universidad de Concepción, Casilla 160-C, Concepción, Chile;2. Department of Geosciences, University of Arizona, Tucson, AZ 85721, USA;3. Escuela Ciencias de la Tierra, Universidad Andres Bello, Campus República, Santiago, Chile;4. Departamento de Geología, Universidad de Chile, Plaza Ercilla 803, Santiago, Chile;5. Universitatea Bucuresti, Facultatea de Geologie Geofizica, Strada N. Balcescu Nr 1, Bucuresti, Romania;6. Institut des Sciences de la Terre d''Orléans (ISTO), 1A rue de la Férolerie, 45071 Orléans Cedex 2, France;7. Minera Escondida, Avenida de la Minería N°501, Antofagasta, Chile;1. Section of Earth and Environmental Sciences, Université de Geneve, Rue des Maraichers 13, 1205 Geneva, Switzerland;2. Instituto Colombiano del Petróleo, Ecopetrol, Bucaramanga, Colombia;1. Departamento de Geociencias, Universidad Nacional de Colombia, Bogotá, Colombia;2. Institut des Sciences de la Terre, Université Grenoble Alpes, Grenoble, France |
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| Abstract: | The Eastern Cordillera of the Colombian Andes represents an inverted Cretaceous basin where Cretaceous magmatism is characterized by rare mafic dykes and sills. We use 40Ar/39Ar, Sr–Nd–Pb isotopes, as well as major and trace elements analyses of Cretaceous intrusions from both flanks of the Eastern Cordillera in combination with structural data to document the complex evolution of the basin. Magmatism, which is diachronous and geochemically diverse, seems to be related to mantle melting beneath the most subsiding segments of each sub-basin during enhanced extensional tectonics. The mafic intrusions display two different compositional series: an alkaline one with OIB-like pattern and a tholeiitic one with MORB-like features. This indicates at least two diverse mantle sources. Trace-element patterns suggest that the intrusions were emplaced in an extensional setting. 40Ar/39Ar dating on primary plagioclase and hornblende provides plateau ages between ～136 and ～74 Ma.The geochemical and temporal diversities show that the emplacement of the magmas was tectonically controlled, each sub-basin reflecting an individual subsidence event. |
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