U-Pb Ages of Zircon Grains in the Playa Azul Beach Sediments, Guerrero State, Mexican Pacific

Abstract

ABSTRACT The mineralogy of bulk sediments, U-Pb ages and chemistry of 195 detrital zircon grains recovered in the Playa Azul beach, Mexican Pacific coast were performed to infer their provenance. The bulk sediments were composed of minerals like quartz, feldspar, titanite, plagioclase, zircon, and magnetite. The average Th/U ratio in zircon grains was ~ > 0.2, indicated an igneous origin. The chondrite normalized rare earth element (REE) patterns of zircons were depleted in low REE (LREE) and enriched in heavy REE (HREE), with positive cerium and negative europium anomalies, indicating a granitoid source. U-Pb ages of zircon grains revealed the predominance of Cenozoic and Mesozoic ages in samples PAC2 (~ 33.8 - 61.8 Ma, n = 90 and ~ 67 - 132 Ma, n = 10, respectively) and PAC19 (~ 0.1 -39.6 Ma, n = 55 and ~ 67 - 251 Ma, n = 20, respectively). Minor peaks were represented by Palaeozoic (n = 9) and Precambrian (n = 11) ages in PAC19. Zircon ages and their morphology indicated that they were mostly derived from the nearby terranes. The source terranes, which supplied Cenozoic zircons to the beach area were the coastal Cenozoic plutons and Cuicateco terrane. The Mesozoic zircons in the Playa Azul coastal sediments were derived from the Mixteca (Acatlan Complex), Guerrero, and Xolapa terranes, located along the Mexican Pacific coastal zone. The Proterozoic zircons were represented by the coastal Oaxacan Complex. In addition, the Arteaga Complex in the Guerrero State, adjacent to the playa Azul beach was the potential source for the Eocene zircons.