Mineralogy and geochemistry of Tecolutla and Coatzacoalcos beach sediments, SW Gulf of Mexico

Mineralogic and geochemical studies were performed in the Tecolutla and Coatzacoalcos beach sediments, located at the SW Gulf of Mexico. The main concern of this article is to infer the weathering, provenance, and degree in which trace metal pollution affects the beach sediment composition. The chemical index of weathering (CIX) for the Tecolutla and Coatzacoalcos beach sediments indicate a moderate intensity of weathering in the source area. The SiO2/Al2O3 ratio values (>6) in the Tecolutla and Coatzacoalcos sediments suggested a high compositional maturity and recycling. A difference in the Al2O3/TiO2 ratios between the Tecolutla and Coatzacoalcos beach sediments points out that the sediments were derived from intermediate and felsic igneous rocks, respectively. A negative correlation for Al2O3 against TiO2 and P2O5, and trace elements Y, Nb, V, Sc, and Cr for the beach sediments suggests an association of these elements with detrital minerals rather than aluminosilicates. The provenance discrimination based on major element concentrations indicates an intermediate and a felsic provenance for the Tecolutla and Coatzacoalcos sediments. The major and trace element geochemistry of beach sediments are associated with a passive margin setting. The Enrichment factor (EF) and Geo accumulation index (I-geo) values show that the Tecolutla sediments are moderately enriched by Cu (EF similar to 10-17) and Cr (1< I-geo <2). An enrichment of EF value for Cu in Tecolutla beach sediments may be a response of anthropogenic and natural sources by the weathering of intermediate igneous rocks. The moderately to highly enriched I-geo values of Pb, Zn, and V observed in the Coatzacoalcos beach sediments, indicate that the sediments were influenced by the waste generated by urban activities in the river drainage catchment area.