Identification of source terranes of beach sediments from the NW Gulf of Mexico, Atlantic ocean: Constraints from geochemistry and U–Pb detrital zircon geochronology

Abstract

This study investigated mineralogy and bulk sediment geochemistry of 24 sediment samples, and U-Pb ages of 200 zircons retrieved from the Tamiahua beach, NW Gulf of Mexico. The study aims to infer the provenance and possible source terranes supplying sediments to the beach area. The XRD and SEM-EDS studies reveal that the sediments are associated with quartz, plagioclase, calcite, and microcline. The Chemical Index of Weathering (CIW'), Th/U and Ba/Sr ratios (>92, 3.75, and 2.27, respectively) indicate high intensity of weathering in the source region. The major as well as trace element-based diagrams along with elemental ratios of TiO₂/Zr (∼15–35), Al₂O₃/TiO₂ (∼120–312), La/Sc (5.31–6.01), La/Co (4.27–5.64), Th/Sc (0.96–1.06), and Cr/Th (3.04–16.24) suggest that the sediments are derived from felsic rocks.

The Th/U ratios of Tamiahua zircons indicate an igneous origin. The chondrite normalized rare earth elements (REE) patterns exhibit positive Ce and negative Eu anomalies and are depleted in light rare earth elements (LREE) and enriched in heavy rare earth elements (HREE). The sediments are dominated with Proterozoic Eon (Mesoproterozoic; 1053.95–1502.36 Ma), Mesozoic Era (Jurassic; 145.42–179.19 Ma and Cretaceous; 68.84–124.45 Ma), and Cenozoic Era (Eocene; 34.08–54.21 Ma and Oligocene; 25.39–33.71 Ma) zircons indicating their derivation from heterogenous source. The Proterozoic zircons in Tamiahua beach sediments are possibly contributed by the Mesa Central Province, which contains zircons from Chiapas and Oaxacan Massif complexes as well as Granjeno schist and Tamatán group from Sierra Madre Oriental Province. Mesozoic zircons are likely contributed by multiple sources, including undifferentiated turbidites of Mesa Central and Zacatecas, Caracol, San Felipe formations and Huizachal group of Sierra Madre Oriental and from Eastern Alkaline Provinces. Similarly, the Cenozoic zircons are supplied by the felsic to intermediate volcanic rocks and granitoids from the Mesa Central Province. The sediment transport and distribution to the beach area is facilitated by the rivers and their tributaries that flow from the source terranes. The results of this study also reveal a passive margin setting for the northwestern Gulf of Mexico.