Initiation of the Mekong River Delta and paleo-environments of lowlands in Cambodia during the Holocene

全新世湄公河三角洲的形成和柬埔寨低地的古环境

• 批准号: 17403010
• 负责人: SAITO Yoshiki
• 金额: $ 8.7万
• 依托单位: National Institute of Advanced Industrial Science and Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17403010/
• 关键词: Mekong River; Southeast Asia; Delta; Holocene; Sea-level change; Paleoenvironment; human activity; mangrove; メコンデルタ

Drilling survey at three sites and seismic survey in the Mekong River in Cambodia were conducted to clarify the initiation of the Mekong River Delta and paleo-environments of lowlands in Cambodia during the Holocene. Quaternary strata in the lowlands consists of at least two marine successions: Holocene and late Pleistocene sediments, bounded by an unconformity. Holocene sediments consist of fluvial sediment, tidal-fluvial sediment, and intertidal to subtidal flat sediment. PSG core located near the border of Vietnam contains marine sediments deposited at inter-to sub-tidal flat environment with ages of 8000-8300 cal BP, meaning that the shoreline was located more landward in Cambodia at that time. This marine inundation was occurred by a rapid sea-level rise during 8500-8400 cal BP abruptly, which will be correlated with 8.4-8.5 ka meltwater pulse. Just after the inundation, the Mekong River Delta was initiated at about 8.3 ka and has prograded with aggradational accumulation of 5m-thick peaty sediments distributed widely around Phnom Penh. Tide-dominated environment was changed into more fluvial dominated environment since 6.7 ka to the present with influences of human activities for the last 2 ka.

在全新世期间，进行了柬埔寨湄公河的三个地点和地震调查，以阐明柬埔寨低地的湄公河三角洲和古环境的启动。低地低地的第四纪地层至少由两个海洋演替组成：全新世和晚更新世沉积物，受到不整合的范围。全新世沉积物由河流沉积物，潮汐沉积物和潮汐扁平沉积物的潮间带组成。位于越南边界附近的PSG核心包含沉积在潮汐间平坦环境中，年龄为8000-8300 cal BP，这意味着当时的海岸线位于柬埔寨的陆地。这种海洋淹没发生在8500-8400 CAL BP中的快速海平面上升发生，这将与8.4-8.5 ka Meltwater Pulse相关。在淹没后，湄公河三角洲的启动约为8.3 ka，并以5m厚的泥炭沉积物的浓度积聚在金边广泛分布。自6.7 ka以来，以潮汐为主的环境变成了更河流主导的环境，并在最后2 ka中受到人类活动的影响。

项目成果

地球史が語る近未来の環境

地球历史讲述的近未来环境

• 发表时间: 2007
• 作者: Ishikawa Shingo (eds. Sakio;H. & Tamura;T. );岩田修二
• 通讯作者: 岩田修二

Sediment facies change and delta evolution during Holocene in the mekong River Delta, Vietnam. In 「Mega-Deltas of Asia : Geological evolution and human impact」

越南湄公河三角洲全新世沉积相变化和三角洲演化，《亚洲巨型三角洲：地质演化和人类影响》。

• 发表时间: 2005
• 作者: 阿部弘典;幸左賢二;西岡勉;田崎賢治;K.Haraguchi;Ta Thi Kim Oanh
• 通讯作者: Ta Thi Kim Oanh

Characteristics and recent environmental changes of large river deltas in Asia. In 「Proceedings of International Sumposium on Long-Term variations in the Coastal Environments and Ecosystems」

亚洲大河流三角洲的特征和近期环境变化，载于“沿海环境和生态系统长期变化国际研讨会论文集”。

• 发表时间: 2005
• 作者: Saito;Yoshiki
• 通讯作者: Yoshiki

Deltaic coast dynamics. In 「Coastal Fluxes in the Anthropocene」

三角洲海岸动力学。

• 发表时间: 2005
• 作者: Saito;Yoshiki
• 通讯作者: Yoshiki

Depositional facies and radiocarbon ages of a drill core from the Mekong River lowland near Phnom Penh,Cambodia

柬埔寨金边附近湄公河低地钻芯的沉积相和放射性碳年龄

• 发表时间: 2007
• 期刊: Journal of Asian Earth Sciences 229・5-6
• 作者: Suzuki;K.;Senda;R.;Honda;M.;Abe;K.;Shinotsuka;K.;Miyata;Y.;Toru Tamura
• 通讯作者: Toru Tamura