Publicaciones

A climatic trigger for catastrophic Pleistocene–Holocene debris flows in the Eastern Andean Cordillera of Colombia

Journal

Journal of Quaternary Science

afiliacion

  1. N. Hoyos, nbotero@uninorte.edu.co, Corporación Geológica ARES, Bogotá, Colombia. Departamento de Historia y Ciencias Sociales, Universidad del Norte, Barranquilla, Colombia. Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panamá
  2. O. Monsalve, Corporación Geológica ARES, Bogotá, Colombia
  3. G.W. Berger, Desert Research Institute, Reno, NV, USA
  4. J. L. Antinao, Desert Research Institute, Reno, NV, USA. Centro Nacional de Investigación para la Gestión Integrada de Desastres Naturales (CIGIDEN), Chile
  5. H. Giraldo, Corporación Geológica ARES, Bogotá, Colombia
  6. C. Silva, Corporación Geológica ARES, Bogotá, Colombia
  7. G. Ojeda, Subsuelo3D S.A.S, Bogotá, Colombia
  8. G. Bayona, Corporación Geológica ARES, Bogotá, Colombia
  9. J. Escobar, Smithsonian Tropical Research Institute, Balboa, Ancón, Republic of Panamá. Departamento de Ingenieria Civil y Ambiental, Universidad del Norte, Barranquilla, Colombia
  10. C. Montes, Corporación Geológica ARES, Bogotá, Colombia. Departamento de Geociencias, Universidad de los Andes, Bogotá, Colombia

Abstract

The geomorphology and stratigraphy of massive debris flows on the Eastern Andean Cordillera, Colombia, indicate two distinct deposits can be recognized. The lower Chinauta deposit covers 14 km2 and has a thickness of ∼60 m, whereas the upper Fusagasugá deposit covers 20 km2 and has a thickness of ∼20 m. The lower Chinauta section consists of matrix-supported gravels, with isolated boulders and massive to moderately bedded structure and local inverse grading. The upper section displays sequences of inversely graded, clast-supported gravels, with boulders >2 m in axial length, capped by massive, matrix-supported fine gravels. The latter are dissected by coarse, channelized gravels. We interpret these facies as a series of debris and hyper-concentrated flows dissected by river channels. The Fusagasugá deposit is dominated by massive to inversely graded matrix-supported gravels with isolated boulders. Single-grain, optically stimulated luminescence dates of the sandy–silty matrix of debris and hyper-concentrated flows constrain the timing of deposition of the Chinauta debris flow deposits between 38.9 and 8.7 ka. We postulate that millennial-scale climate variability is responsible for causing these massive debris flows, through a combination of elevated temperatures and increased rainfall that triggered runoff and sediment transport.

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