Geomorfología y Sedimentología del sector medio del valle de pueblo llano, Andes de Mérida, Venezuela

Geomorphology and Sedimentology in the middle reach of the pueblo llano Valley, Mérida Andes, Venezuela

  • Oswaldo Guzman Universidad Simón Bolívar - Venezuela
  • Corina Campos Universidad Regional Amazónica - Ecuador
  • Merlus Ruiz Universidad Simón Bolívar - Venezuela
  • Isandra Angel Universidad Simón Bolívar - Venezuela
  • Riccardo Vassallo Université de Savoie Mont-Blanc - Francia
  • Nataly Aranda Universidad de São Paulo - Brasil

Resumen

Un análisis geomorfológico y sedimentológico fue realizado en el sector medio del Valle de Pueblo Llano con la finalidad de comprender la génesis de los sedimentos y geoformas cuaternarias presentes en el área. Cuatro sectores con características morfológicas y sedimentológicas distintivas fueron identificados: (i) depósitos en masa de flujos de detritos con una expresión superficial cónica interpretados como abanicos aluviales, (ii) depósitos de flujos unidimensionales que constituyen terrenos relativamente planos con bajas pendientes característicos de terrazas fluviales, (iii) depósitos de diamicton que constituyen un conjunto de lomos y depresiones en forma de arco asociados a un complejo de morrenas frontales, y (iv) depósitos de flujos unidimensionales que conforman terrenos con forma de lomos asimétricos, asociados a condiciones fluvio-glaciares. Estos resultados ponen en evidencia que los glaciares asociados a la Glaciación Mérida en el Valle de Pueblo Llano, alcanzaron elevaciones al menos 300 m más bajas que las reportadas previamente en la literatura para los Andes de Mérida. Además, sugieren que otros valles glaciares presentes en los Andes de Mérida pudieron haber experimentado fenómenos similares.
 
Palabras clave: Andes de Mérida, Geomorfología y Sedimentología, Morrenas, Glaciación Mérida, Pueblo Llano.
 
Abstract:
A geomorphological and sedimentological analysis was carried out in the Middle reach of the Pueblo Llano Valley to understand sediment genesis and quaternary geoforms present in the area. Four zones with distinctive morphological and sedimentological characteristics were identified: (i) mass deposits of debris flow with a cone-shaped surface interpreted as alluvial fans, (ii) unidirectional flow deposits with relatively flat topography, with little slope, characteristic of fluvial terraces, (iii) arc-shaped diamicton deposits that constitute a set of crests and valleys, associated to a complex of frontal moraines, and (iv) unidirectional flow deposits that form terrains with the shape of asymmetric ridges, associated to a fluvio-glacial conditions. These results show that the glaciers of the Mérida Glaciation in the Pueblo Llano Valley reached elevations of at least 500 m lower than those previously reported in the literature for the Mérida Andes. In addition, they suggest that other glacial valleys present in the Andes of Mérida might have experienced similar phenomena.
 
Keywords: Mérida Andes, Geomorphology and Sedimentolology, Moraine complex, Mérida Glaciation, Pueblo Llano.

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Publicado
2019-12-01