Abstract

CARRANZA-EDWARDS, Arturo et al. Morphologic and sedimentologic changes in beaches of the southern Gulf of Mexico and the northwestern Caribbean. Bol. Soc. Geol. Mex [online]. 2015, vol.67, n.1, pp.21-43. ISSN 1405-3322.

This study aims to compare morphological and sedimentological variations between the beaches of the Southern Gulf of Mexico and the Riviera Maya (Northwest Caribbean) by conducting two regional samplings of foreshore sediments, measuring topographic profiles of the beaches, and analyzing the potential impact of sea level rise from global warming. The time lapse between samplings was 26 and 32 years. Beach profiles, shoreline changes, textural parameters and composition of surficial beach sands from the foreshore were compared. This study considers the state of tide, rainfall and meteorological events. A total of 23 beach locations were studied: 19 for the Southern Gulf of Mexico and 4 for the Riviera Maya. The beach profiles show variations, with recent beaches sometimes being wider than the ancient ones. The concavity of the recent exposed beach profiles suggests that many of them are eroding. The coastline contours were analyzed through LANDSAT images from several years. Variations of coastlines in different years suggest the influence of anthropogenic and meteorological processes, indicating a connection between deposition and erosion of beaches at locations that are not very far from each other. The comparisons of textural and compositional parameters proved to be useful in the comparative analysis of ancient and recent beach sands. It is noted that it is more common for recent sediments to be more poorly sorted compared to ancient sediments, which may suggest greater interference of anthropogenic factors in recent sediments or a greater variation in oceanographic parameters. The greater statistical weight is observed through principal component analysis and is given by heavy minerals in terrigenous sands, and in carbonate sediments by pellets; this relation reflects favorable conditions for erosion and a probable depletion of marine littoral organisms and birds.

Keywords : Gulf of Mexico; Riviera Maya; foreshore; beach face; sediment texture; sand composition; coastlines.