programme tuesday, july, 31 - Université de Caen Basse Normandie

Tidalites 2012, 8th International Conference on tidal environments, Caen, France – Abstract book
BAEKSU OPEN-COAST TIDAL FLAT OF THE KOREAN WEST SEA COAST
REVISITED: A DEPOSITIONAL MODEL AND ITS PRESERVATION POTENTIAL
Taesoo CHANG
KOREA INSTITUTE OF GEOSCIENCE & MINERAL RESOURCES, #124, Gwahang-No, Yuseong-Gu,
305-350, Daejeon, Korea, tschang@kigam.re.kr
In a recent year, open-coast tidal flats and its ancient analogues have been increasingly
received attention, as they are a hybrid depositional system controlled by the interaction of waves
and tides. In a consequence, some attempts were made to distinguish between a classical tidal
flat and wave-dominated tidal flat, and between tidal shoreface and open-coast tidal flat too (Yang
et al., 2005, 2008; Basilici et al., 2011; Fan, 2012). Baeksu open-coast tidal flats were previously
reported as such a typical hybrid coastal system, wave-dominated in winter and tide-dominated in
summer due to the seasonal wind distribution. However, the arguments for this open-coast tidal
flat model were raised and alternative interpretations suggested as two facies models, an
intertidal shoreface for outer part and an estuarine tidal flat model for inner part (Chang and
Flemming, 2006). In this regard, we revisited on the open-coast tidal flats in order to fulfill the
arguments and to discuss a depositional model for hybrid tidal flats with respect to preservation
potential. For this purpose, over 200 surface sediments were taken from intertidal to subtidal
regions using a grab-sampler. Vibro-coring was carried out along the two transects placed across
the reclaimed area.
The Baeksu tidal flats are 6~10 km wide and ~10 km long and it opens directly to the Yellow
Sea without any barriers and the coast-oblique subtidal sand bars boarder the seaward margin of
the tidal flats. Near the high-tide line, the artificial dikes were built and the upper flats have been
reclaimed over the century. Beyond the reclaimed area where the villages are located, the
degraded coastal dune fields occur. The only topographic features on the flats are the low-relief,
shore-parallel swash bars and tidal channels are restricted to upper mud flats and salt marshes.
The tide is semidiurnal with a mean tidal range of 3.9 m, corresponding to the lower macrotidal
regime. The wind regime is predominantly influenced by the monsoon, leading to strong
seasonality. Significant wave heights vary between