2015 Volume 124 Issue 4 Pages 665-674
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.