ABSTRACT

Late Pleistocene silty tidal rhythmites in Kyunggi Bay, west coast of Korea, demonstrate various rhythmicities in lamina thickness associated with hierarchical tidal cycles ranging from semidiurnal to monthly (anomalistic) tidal variation. Such rhythmicities are very similar to those of modern tidal cycles in Kyunggi Bay, implying that late Pleistocene tides in Kyunggi Bay were similar to those of the present day. Hourly modern tides were analyzed as event series to simulate the late Pleistocene rhythmites, and they were truncated at different reference levels to simulate intertidal rhythmites, whereby relative position within the tidal frame was used as a threshold for lamina deposition. Comparison of spectral peaks between late Pleistocene and simulated rhythmites suggests that deposition of the rhythmites might occur in the upper intertidal flat, possibly near mean high water level and at least not higher than mean spring high water level in the case of a gradual decrease of accommodation space through deposition.