Detrital zircon typology and U/Pb geochronology for the Miocene Ladrilleros-Juanchaco sedimentary sequence, Equatorial Pacific (Colombia): New constraints on provenance and paleogeography in northwestern South America

Authors

  • E. OSORIO-GRANADA Universidad de Caldas, Facultad de Ciencias, Departamento de Ciencias Geológicas Grupo de Investigaciones en Estratigrafía y Vulcanología (GIEV-Cumanday), Instituto de Investigaciones en Estratigrafía (IIES), Manizales, Colombia.
  • S.A. RESTREPO-MORENO Departamento de Geociencias y Medio Ambiente, Universidad Nacional de Colombia Sede Medellín Department of Geological Sciences. University of Florida Gainesville, Florida 32611, USA
  • J.A. MUÑOZ-VALENCIA Universidad de Caldas, Facultad de Ciencias, Departamento de Ciencias Geológicas Grupo de Investigaciones en Estratigrafía y Vulcanología (GIEV-Cumanday), Instituto de Investigaciones en Estratigrafía (IIES), Manizales, Colombia.
  • R.A. TREJOS-TAMAYO Universidad de Caldas, Facultad de Ciencias, Departamento de Ciencias Geológicas Grupo de Investigaciones en Estratigrafía y Vulcanología (GIEV-Cumanday), Instituto de Investigaciones en Estratigrafía (IIES), Manizales, Colombia.
  • A. PARDO-TRUJILLO Universidad de Caldas, Facultad de Ciencias, Departamento de Ciencias Geológicas Grupo de Investigaciones en Estratigrafía y Vulcanología (GIEV-Cumanday), Instituto de Investigaciones en Estratigrafía (IIES), Manizales, Colombia.
  • A.A. BARBOSA-ESPITIA Universidad de Caldas, Facultad de Ciencias, Departamento de Ciencias Geológicas Grupo de Investigaciones en Estratigrafía y Vulcanología (GIEV-Cumanday), Instituto de Investigaciones en Estratigrafía (IIES), Manizales, Colombia. Department of Geological Sciences. University of Florida Gainesville, Florida 32611, USA

Keywords:

Miocene, Ladrilleros-Juanchaco sedimentary sequence, Colombia western Cordillera, Provenance

Abstract

Typology and internal texture analyses were performed on detrital zircons obtained from the Miocene sandstones of the Ladrilleros-Juanchaco sedimentary sequence (Colombia, Equatorial Pacific). This analysis was complemented with zircon U/Pb dating to identify typology-age associations as indicators of sediment provenance. Our results show that zircons with S and P dominant typologies have internal structures/zoning indicative of igneous, and potentially also metamorphic, origins. Morphometric results suggest limited transport from source areas. Both typology and U/Pb data point to the western Cordillera as the principal source of detrital materials for this sedimentary sequence. A paleogeographic reconstruction shows that, during the Late Miocene, significant portions of the western Cordillera were uplifted and actively eroding, thereby forming a fluvio-topographic barrier that prevented sediments from the central Cordillera reaching the Pacific basins. Exhumed Miocene plutons located along the axis of the western Cordillera may also have played a role as geomorphologically active massifs. This study demonstrates that typologic analysis on detrital zircon grains is a useful tool for establishing provenance and paleogeography in complex litho-tectonic areas where overlapping U/Pb signatures can lead to contradictory results.

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Published

2017-09-04

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