Cretaceous extensional and compressional tectonics in the Northwestern Andes,prior to the collision with the Caribbean oceanic plateau |
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| Institution: | 1. Facultad de Minas, Universidad Nacional de Colombia, Cr. 80 # 65-223, Medellín, Colombia;2. Corporación Geológica ARES, Calle 44A N. 53-96, Bogotá D.C., Colombia;3. Institute of Earth and Environmental Sciences, University of Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam, Germany;4. Departamento de Procesos y Energía, Universidad Nacional de Colombia, Cr. 80 # 65-223, Medellín, Colombia;5. School of Earth and Environment, Washington State University, Pullman, United States;6. Instituto de Investigaciones en Estratigrafía-IIES, Universidad de Caldas, Calle 65 N° 26-10, Manizales, Colombia;1. Departamento de Geociencias y Medio Ambiente, Facultad de Minas, Universidad Nacional de Colombia, Carrera 80 No. 65-223, Medellín, Colombia;2. Departamento de Ciencias de la Tierra, Universidad EAFIT, Carrera 49 No. 7 Sur-50, Medellín, Colombia;3. Centro de Geociencias, Universidad Nacional Autónoma de México, Querétaro 76230, Mexico;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;2. Institute of Energy and Environment, University of São Paulo, São Paulo, Brazil;3. Institute of Earth and Environmental Sciences, University of Potsdam, Potsdam, Germany;4. GFZ German Research Center for Geosciences, Potsdam, Germany;5. Norwegian Computing Center, Oslo, Norway |
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| Abstract: | The Cretaceous units exposed in the northwestern segment of the Colombian Andes preserve the record of extensional and compressional tectonics prior to the collision with Caribbean oceanic terranes. We integrated field, stratigraphic, sedimentary provenance, whole rock geochemistry, Nd isotopes and U-Pb zircon data to understand the Cretaceous tectonostratigraphic and magmatic record of the Colombian Andes. The results suggest that several sedimentary successions including the Abejorral Fm. were deposited on top of the continental basement in an Early Cretaceous backarc basin (150–100 Ma). Between 120 and 100 Ma, the appearance of basaltic and andesitic magmatism (~115–100 Ma), basin deepening, and seafloor spreading were the result of advanced stages of backarc extension. A change to compressional tectonics took place during the Late Cretaceous (100–80 Ma). During this compressional phase, the extended blocks were reincorporated into the margin, closing the former Early Cretaceous backarc basin. Subsequently, a Late Cretaceous volcanic arc was built on the continental margin; as a result, the volcanic rocks of the Quebradagrande Complex were unconformably deposited on top of the faulted and folded rocks of the Abejorral Fm. Between the Late Cretaceous and the Paleocene (80–60 Ma), an arc-continent collision between the Caribbean oceanic plateau and the South-American continental margin deformed the rocks of the Quebradagrande Complex and shut-down the active volcanic arc. Our results suggest an Early Cretaceous extensional event followed by compressional tectonics prior to the collision with the Caribbean oceanic plateau. |
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