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The provenance of sands from the Manzanillo (MN) and El Carrizal (CAR) beach areas along the Mexican Pacific coast (southern Mexico) was investigated based on their modal composition, mineralogy and geochemical data. The average quartz, feldspar and lithic fragment (QFL) ratios revealed that the proportion of quartz is higher in CAR sands than in MN sands. In comparison with MN, the CAR sands are enriched in SiO2 content with higher SiO2/Al2O3 ratio indicating that sediment recycling is greatest for the CAR sands. The variation in K2O/Al2O3 and Na2O/K2O ratios between the MN and CAR sands specified a difference in the relative proportion of plagioclase. The chemical index of alteration (CIA) and Plagioclase Index of Alteration (PIA) values revealed a moderate weathering intensity in the source areas. The MN sands are characterized by a low degree of rare earth element (REE) fractionation (LaCN/YbCN = ~6–7), whereas the CAR sands define fractionated REE patterns (LaCN/YbCN = ~8.8–16.8). The fractionated REE pattern with elevated total low REE (∑LREE) content of the CAR sands suggested that sediment sorting is higher for the CAR than MN sands. Small negative and positive Eu anomalies (Eu/Eu* = ~0.91–1.23) of MN sands indicated the derivation of sediments from felsic‐intermediate source rocks. The CAR sands showed higher concentration of ∑LREE than total heavy REE (∑HREE) and characterized by a significant negative Eu anomaly (Eu/Eu* = ~0.46–0.78), suggested that the source rock is felsic type. The result obtained by the comparison of REE patterns of the beach sands to the probable source rocks is also consistent with this observation. The compositional differences identified between the MN and CAR beach areas suggested that longshore current in the mixing and homogenization of sands is not significant. The new tectonic discriminant‐function‐based multidimensional diagrams showed an arc setting (active) for the MN sands and a rift setting (passive) for the CAR sands, which is consistent with the regional geology of southern Mexico. Copyright © 2016 John Wiley & Sons, Ltd.

Th, P, and Hf were immobile and Cu, Cr, and Zn were mobile during alteration processes. However, Torres-Alvarado et al. (2007) recently studied the effect of hydrothermal alteration on the chemistry of volcanic rocks from the Los Azufres geothermal field, Mexico, and found that most major elements and a few trace elements, including high field strength elements such as Zr, Ti, and P, were mobilized during hydrothermal alteration. They cautioned against the use of these elements for petrogenetic studies of igneous and metamorphic rocks. Although provenance studies are common (Hossain et al., 2010(Hossain et al., , 2014Armstrong-Altrin and Natalhy-Pineda, 2013), studies focused on the geochemical variation in sediments with respect to grain size are meagre (e.g., Ohta, 2008;Effoudou-Priso, 2014).The study areas of the San Nicolás (SN) and San Carlos (SC) beaches are located along the Gulf of California.

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A sedimentological, petrographic, and geochemical study of beach, dune, and river sands was carried out along the northwestern Gulf of Mexico. The main goal of this work is to show how beach and dune sands are controlled texturally, compositionally, and chemically by the nearby rivers for each beach location using a particle size analyser, a polarized microscope, a X-ray fluorescence and ICP mass spectrometer to obtain the following: grain-size values from one river (Carrizal River) are similar in range to their counterpart beach sands but not similar to the dune sands (Barra del Tordo). Rivers (Panuco and Carrizal) are compositionally controlling the quartz and feldspar contents of their counterpart beach and dune sands (i.e., Playa Miramar and Barra del Tordo). Rivers (Soto La Marina River) are directly influencing the composition of the beach sands (La Pesca) based upon the total quartz content, beach and dune sands. The concentration of magnetite grain fractions (Barra del Tordo beach and dune sands) is not under the influence of the nearby river (Carrizal River). In this case the compositional influence of beach and dune sands is related to sediment discharges by other fluvial systems, redistribution of the beach and dune sands along the coast and deflation/winnowing of light minerals. The Eu positive anomaly in the beach and dune sands from the three sites (i.e. Playa Miramar, Barra del Tordo, La Pesca) is linked to an increase in the P(plagioclase)/K(potash feldspar) ratio. The (La/Lu) cn highest ratio for river sands (Carrizal River) suggests quartz enrichment compared to their beach and dune sands counterparts. The (Gd/Yb) cn ratio for one river (i.e., Carrizal River) indicates that it is low in heavy rare earth elements. HREE compared to their beach and dune sands counterparts indicates less concentration of heavy minerals as potential carriers of HREE seawards.