10월 27일(수)
․층서퇴적학 | 석유지지질학
40 2010 추계지질과학연합학술발표회 초록집
Sedimentary facies and morphodynamics of intertidal channel in Yeochari tidal flat, Kyonggi Bay
Changmin Hong
*․Kyungsik Choi Faculty of Earth Systems and Environmental Sciences,
Chonnam National University, [email protected]
Up to 6-km wide, extensive tidal flats are developed at Yeochari, sourthern Ganghwa Island in the macrotidal Han River delta, west coast of Korea. The flats are divisible into two morphologic zones, a monotonous, concave-up upper intertidal flat and a channelized, middle to lower intertidal flat. Along the transect YC-1, four channels (CH-1, CH-2, CH-3, and CH-4 from seaward to landward) are recognized in the lower to middle intertidal flat. The channels are 240-570 m wide and 1.2-2.4 m deep. Repeated profilings of YC-1 using a total station and RTK GPS revealed that channels are actively migrating at a remarkable rate. In particular, CH-4 migrated about 100 m during 10 months, resulting in the rapid deposition of interlaminated sands and muds that constitute inclined heterolithic stratification (IHS) of a point bar. Erosion remnants of the IHS exposed on the present cut-bank of CH-4 indicate that channel migration is multidirectional and extensive. Long-term observations of channel morphology suggest that tidal channels are highly mobile to form complicated architecture of channel-bank deposits. Considering the seasonality of precipitation due to monsoon climate, the mobility of tidal channels seems to be pronounced presumably during summertime rainy season when ebb currents are reinforced by increased runoff discharge.
Tidal channels in the Yeochari tidal flat are comparable in size and facies architecture to heterolithic oil sand reservoirs encountered in Alberta, Canada. Results of this study may facilitate better characterization of estuarine to deltaic tidal channel reservoirs, which were formed by interaction between tide, wave and river with the presence of strong climate influence.
구두 5-3
