Progradation of a Beach Ridge Plain between 5000 and 4000 Years BP Inferred from Luminescence Dating, Coquimbo Bay, Chile

Abstract

ABSTRACT Hart, E.A.; Stapor, F.W.; Enrique Novoa Jerez, J., and Sutherland, C.J., 2017. Progradation of a beach ridge plain between 5000 and 4000 years BP inferred from luminescence dating, Coquimbo Bay, Chile. Luminescence dating was carried out to determine the depositional history of a 2-km-wide, shore-parallel, beach ridge sequence at Coquimbo Bay, Chile, for which no direct dating had previously been done. The beach ridge plain at Coquimbo Bay represents one of the most extensive Holocene depositional features preserved along the Pacific Coast of South America. Both optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL) dates indicate a rapid period of beach ridge progradation lasting approximately 1000 years at an average rate of 2 m y−1. However, based on previously reported luminescence deficiencies of geologically “young” quartz, it is proposed that IRSL dates are more representative of the actual depositional age of the beach ridges. These IRSL ages indicate that the...