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Geomorphological characteristics of longitudinal coastal dunes of the Isthmus of Médanos, Falcón state, Venezuela

Abstract:

This paper analyzes the geomorphological characteristics of longitudinal coastal dunes of the Isthmus of Medanos, at Falcon state, northwestern Venezuela. The methodology used was based on field work, sedimentological analysis, cartographic, photogrammetric and satellite interpretation. The results shows that the sediments are fine grain sand (84.6%), well selected by over 60%, mainly subangular, with predominantly negative asymmetry, leptokurtic distribution, and low-carbonate contents (10%). The data suggest a terrigenous source of sediments that evidence short transport distance. The current prevailing winds are from the Northeast with secondary directional components that reworked sediments and produced dunes like barchans, transverse and longitudinal dunes; the longitudinal dunes are parallel to the wind direction, and colonized by xerophitic plants. These dunes probably were originated by a combination of factors including: availability of sediments in a wide coastal plain associated to regressive sea level, strong and persistent winds, oblique orientation of the coast, favorable topography adjacent to the beach and paleoclimatic conditions.