Geochemistry and U-Pb geochronology of detrital zircons in the Brujas beach sands, Campeche, Southwestern Gulf of Mexico, Mexico

This study investigated the bulk sediment geochemistry, U-Pb ages and rare earth element (REE) geochemistry of one hundred detrital zircons recovered from the Brujas beach sands in southwestern Gulf of Mexico to understand the provenance and age spectra. The bulk sediments are high in Zr and Hf contents (similar to 1400-3773 ppm and similar to 33-90 ppm, respectively) suggested the abundance of resistant mineral zircon. The chondrite normalized REE patterns of the bulk sediments are less fractionated with enriched low REE (LREE; LacN/SmcN = similar to 491-693), depleted heavy REE (HREE; Gd-CN/YbcN = similar to 44-69) and a negative Eu anomaly (Eu/Eu* = similar to 0.44-0.67) suggested that the source rock is felsic type. The results of this study revealed highly varied contents of Th (similar to 4.2-321 ppm), U (similar to 20.7-1680 ppm), and Hf (similar to 6970-14,200 ppm) in detrital zircons compared to bulk sands. The total REE content (similar to 75 and 1600 ppm) and its chondrite-normalized pattern with positive Ce and negative Eu anomalies as well as low Th/U ratio of zircon grains indicated that they were dominantly of magmatic origin. U-Pb data of zircons indicated two age populations, with predominance of Permian-Triassic (similar to 216 -286 Ma) and Neoproterozoic (similar to 551-996 Ma). The Permian - Triassic zircons were contributed by the granitoids and recycled metasedimentary rocks of the Chiapas Massif Complex. The major contribution of Neoproterozoic zircons was from the Chaucus, Oaxacan, and Chiapas Massif Complexes in Grenville Province, southern Mexico. U-Pb ages of zircons from the Brujas beach are consistent to the reported zircon ages from the drainage basins of Usumacinta, Coatzacoalcos, and Grijalva Rivers in southern Mexico, suggesting that the sediments delivered by the rivers to the beach area are vital in defining the provenance of placers. (C) 2017 Elsevier Ltd. All rights reserved.