U.S.- Vietnam Planning Visit: Study of the Mekong River-derived sediment in the South China Sea

[05143093]该奖项支持计划访问，使罗利北卡罗莱纳州立大学的J Paul Liu教授和David De Master教授能够与罗利北卡罗莱纳州立大学的J Paul Liu教授和David De Master博士会面。越南科学技术研究院（VAST）的Van Lap Nguyen和Thi Kim Oanh Ta。这次访问将有助于制定一项详细的合作计划，以研究湄公河在南部的沉积物。湄公河是东南亚最大的河流之一，从青藏高原向南流经印度支那半岛，流入世界上最大的边缘海——南海。它长4200公里，目前每年的输沙量约为1.6亿吨。现代湄公河三角洲形成于过去6000-7000年间，从那时起，从柬埔寨边境一直延伸到现在的海岸线200多公里。然而，大量的沉积物也被怀疑逃离了三角洲系统，分散到南海，并向西南方向输送到泰国湾。目前，人们对与湄公河扩散体系相关的河流衍生的发现颗粒沉积物的分布和厚度知之甚少。人们希望知道有多少河流沉积物和有机物被埋在近岸陆架沉积物中（有机碳保存率相对较高的地点），有多少被运往离岸较深的水域（有机碳保存效率相当低）。为了定量确定湄公河沉积物的命运，并评估分散系统大陆架范围内的有机碳埋藏，研究人员将利用新的高分辨率X-Star啁啾亚底剖面仪和沉积物取心对湄公河三角洲内大陆架泥沉积进行研究。这次访问将使研究人员能够评估越南的设施、设备和现有的数据集。然后，他们可以确定未来巡航的方法和时间表。他们还将设计一个机制，安排美国和越南的科学家和学生互访。该研究项目的结果将有助于海洋科学界了解河流主导的海洋边缘的沉积和碳埋藏。这种陆表环境的研究重点与NSF的几个跨学科项目是一致的，包括陆地-海洋相互作用（LOICZ）、源-汇（海洋地质和地球物理学）、RiOMar（河流主导的海洋边缘）和碳倡议。访问和合作研究将通过在越南和美国机构和科学家之间建立伙伴关系产生更广泛的影响。它还为支持年轻海洋地质学家的发展和学生和科学家的互访提供了一个极好的机会，同时促进了创新的、国际的、跨学科的科学研究。

0514309LiuThis award supports a planning visit to enable Professors J Paul Liu and David De Master of the North Carolina State University in Raleigh to meet with Drs. Van Lap Nguyen and Thi Kim Oanh Ta of the Vietnamese Academy of Science and Technology (VAST). The visit will help develop a detailed collaborative plan to study the Mekong River-derived sediment in the South. The Mekong River, one of the largest rivers in Southeast Asia, flows southward from the Tibetan Plateau to the South China Sea (SCS), the largest marginal sea in the world, through the Indochinese Peninsula. It is 4200 km long and the sediment discharge of the river is currently about 160 million tons per year. The modern Mekong River delta was formed during the past 6000-7000 years, and since then, has prograded more than 200 km from the Cambodian border to it present coastline. However a huge amount of sediment also is suspected to escape the deltaic system, to disperse into the SCS, and to be transported southwest into the Gulf of Thailand. At present there is little knowledge about the distribution and thickness of the river-derived find-grained deposits associated with the Mekong dispersal system. It would be desirable to know how much riverine sediment and organic matter is buried in nearshore shelf deposits (sites of relatively high organic carbon preservation) and how much is transported offshore to deeper waters (with considerably lower organic carbon preservation efficiencies). In order to quantitatively determine the fate of Mekong River sediment and evaluate organic carbon burial within the continental shelf reaches of the dispersal system the researchers will focus on a study of the inner shelf mud deposit of the Mekong Delta using the new high-resolution X-Star Chirp Sub-bottom Profiler and sediment coring. This visit will enable the researchers to assess Vietnamese facilities, equipment, and existing data sets. They can then determine methods and schedules for future cruises. They will also devise a mechanism for arranging exchange visits for US and Vietnamese scientists and students. Results of the research project will help the marine science community understand sedimentation and carbon burial on a river-dominated ocean margin. The focus of the research in this epicontinental environment is consistent with several interdisciplinary NSF initiatives including Land-Ocean Interaction (LOICZ), Source-to-Sink (Marine Geology and Geophysics), RiOMar (River-dominated Oceanic Margins) and the Carbon Initiative. The visits and collaborative research will have broader impacts through partnership building among Vietnam and US institutions and scientists. It also provides an excellent opportunity to support the development of young marine geologists and to conduct exchange visits of students and scientists while promoting innovative, international, interdisciplinary scientific studies.