Rasgos de levantamiento de la margen continental a partir del oligoceno: contribución al conocimiento del Noreste Colombiano

Abstract

During geomorphologic survey carried out on the coastal zone at the Department of La Guajira, Colombia, signs of active upwelling at the Northern continental margin of South-America were described, which are closely related to the Oca Fault. This is the north limit of the structural and triangular staff named Sierra Nevada de Santa Marta(SNSM). Results are really important to General Maritime Direction and its Research Center because they become a scientific support for the analysis of hazard due to coastal erosion, as conditioning agents of the administrative performance on the areas under the jurisdiction of the maritime authority around the Caribbean coastal zones of Colombia. Cartography scale 1:25000 and 1:50000 produced by Oceanographic and Hydrographic Research Center CIOH, was useful to provide better details than other similar approaches, in order to define the superficial geomorphologic and quaternary lithologic units (1.75M. y. orless) and high instability coastal zones. This case-study illustrates possible relationship between : a) the SNSM presence and recent activity of the Oca-Ancon, Guajira-Paraguana and Cuiza-Bocono Faults; and b) sectors that show high erosion (typical geomorphologic features). Other geomorphologic features observed close to northern La Guajira Peninsula's coastal sector, as well as sea cliff sand high sea abrasion surfaces (wave-cut platforms) on marine young deposits suggest sudden upwelling of coastal margin after the Paleocene had ended (23.5M. y. ago). The Present study is only the start of a series of subsequent analyses and activities more elaborated, that are intended to ratify the findings and to go deep in to Colombian Caribbean coastal margin geologic knowledge.