Report on Calibrated Radiocarbon Ages of Beachrock Samples and Consolidated Deposits at Nyateya-gama Cave on Ie Island, Okinawa, Japan

Abstract

 A total of 27 beachrock and consolidated samples were collected from Ie Island, Okinawa, to determine their accumulation ages and/or formation of beachrock. They were radiocarbon dated and their stable carbon isotope ratios (δ¹³C) were measured to correct radiocarbon ages. Beachrocks were formed from ca. 4,600 cal BP until around 690 cal BP. Nyateya-gama cave is a sea-cave whose floor sediments have been partially consolidated since ca. 3,600 cal BP. The characteristics of the deposits resemble beachrock; however, they do not indicate a typical cuesta topography.