Grain-size trends and provenance of southwestern Gulf of Mexico beach sands

Abstract

Sand samples from 30 beach locations of the southwestern Gulf of Mexico littoral zone were texturally and mineralogically investigated. Based on their source lithology and fluvial network, they were subdivided into two groups: (1) sands with volcanic rocks in the source region and (2) sands with a nonvolcanic source. Sands from foreshore and backshore areas exhibit similar textural characteristics, with less rock fragments than those from the inshore zone, where the high energy of breaking waves and littoral currents is present. A quartz–feldspar–rock fragment triangular diagram indicates that the proximity of volcanic sources is responsible for the enrichment of rock fragment content in the beach sands. Beach sands associated with Tampico and Veracruz embayments have greater quartz content, caused by a greater transport distance. Mineralogical maturity and provenance indexes used in a binary diagram are helpful in discriminating sand samples from volcanic and nonvolcanic domains.