Holocene Antarctic melting and lithospheric uplift history of the southern Okinawa trough inferred from mid- to late-Holocene sea level in Iriomote Island, Ryukyu, Japan

摘要

Relative sea level deduced from fossil oysters and mangroves are reported for Iriomote Island, Ryukyus, southwestern Japan. Radiocarbon-dated fossil oysters, as well as previously analyzed mangrove muds, are compared to geophysical and glacio-hydro-isostatic adjustment (GIA) models that describe Earth deformation due to changing surface loading. The Holocene-high-stand (HHS) inferred from oyster fossils (Saccostrea echinata and Saccostrea malaboensis) is 2.7 m at ca. 3500 years ago, after which sea level gradually fell to present level. The HHS magnitude attributed to GIA for the last ca. 4000 is between 1 and 1.5 m above present day sea level, and the residual indicates the long-term lithospheric uplift rate of the island. The timing of peak HHS also indicates that late Holocene melting mainly from Antarctica ceased by approximately 4000 years ago. (C) 2015 Elsevier Ltd and INQUA. All rights reserved.