文献一覧: Sotham SIENG (著者)

2 0 0 0 OA Floodplain Characteristics of the Mekong Delta in Cambodia

著者: Seiichiro OKETANI Shigeko HARUYAMA Sotham SIENG
出版者: The Association of Japanese Geographers
雑誌: 地理学評論 (ISSN:13479555)
巻号頁・発行日: vol.80, no.12, pp.693-703, 2007-10-01 (Released:2010-03-12)
参考文献数: 21
被引用文献数: 4 4 3

The purpose of this study was to examine the floodplain characteristics of the inner Mekong Delta, on the lower part of the Mekong River in Cambodia. Previous works have not investigated the floodplain characteristics of the fluvial dominated area of the Mekong Delta. To grasp the morphology of the study area, we first constructed topographical profiles from hydrologic maps and Space Shuttle Radar Topography Mission 3 data. Then, focusing on the morphology of the floodplain, we produced a land classification map based on aerial photo interpretation and field survey and identified the morphological structures of the study area. We classified the delta landforms as natural levee, back marsh, abandoned channel, alluvial terrace, swamp, point bar, and artificial landforms, including colmatages. We identified four floodplain zones. Zone A floodplains, along the upper part of the Mekong River, have cut-off point bar patterns. Those in zone B, along the lower part of the Mekong River, are linear, and develop back marsh widely. In zone C, along the Bassac River, the floodplains follow the river meanders, and are characterized by unevenly distributed artificial colmatages. Floodplains in zone D, along the Tonle Sap River, which has an extremely low gradient, display a unique geomorphology caused by seasonally reversed river flows.

2 0 0 0 OA Sedimentary Facies of Borehole Cores from the Mekong River Floodplain in Cambodia

著者: Kazuaki HORI Shigeko HARUYAMA Sotham SIENG
出版者: The Association of Japanese Geographers
雑誌: 地理学評論 (ISSN:13479555)
巻号頁・発行日: vol.80, no.12, pp.681-692, 2007-10-01 (Released:2010-03-12)
参考文献数: 18
被引用文献数: 5 5 4

This study analyzes three borehole cores to examine the sedimentary facies of the extensive floodplain of the Mekong River in Cambodia and discusses the relationship between sedimentary facies and surface topography. Sedimentary facies vary according to surface topographic features on the floodplain. Core PA, located near the end of an abandoned channel, records the history of the formation and subsequent filling of the channel during the Holocene. The channel was filled with interlaminated sand and mud overlain by grayish brown to dull reddish brown stiff mud during the last 4500 years. Core CK was located on the southwestern edge of an area of scroll bars and swales between the Mekong and Bassac rivers. In this core, muddy overbank deposits overlie sandy deposits that probably represent a point bar. The accumulation of the overbank deposits may have started around 2000 cal yr BP. Core TA was obtained from the floodplain along the west bank of the Tonle Sap River. Mottled stiff mud containing granules occurs about 1m below the surface and overlies subangular granules. Muddy overbank deposits corresponding to those of the other two boreholes are not present at the site despite frequent flooding of the Tonle Sap River.