International Research Fellowship Program: Determining Bedrock Incision Rates using Cosmogenic Isotope \3He\ Analysis to Chronologically Constrain the Wetland Development Cycle in

国际研究奖学金计划使美国科学家和工程师能够在国外进行9到24个月的研究。该项目的奖项提供了联合研究的机会，并利用国外独特或互补的设施、专业知识和实验条件。该奖项将支持阿曼达·基恩-泽伯特博士与英国阿伯里斯特威斯威尔士大学的斯蒂芬·图斯博士合作的为期24个月的研究奖学金。湿地是全球保护努力的重点。然而，地貌湿地的研究一直是有限的。在南非高地，冲积河流和基岩河流之间的关系对湿地的稳定性产生了影响，而湿地是亚湿润到半干旱地区的重要水资源。该项目的研究人员正在调查影响南非湿地发展和稳定性的长期发展和沉积学因素。研究人员正在为该地区湿地发展的概念模型增加一个时间元素，该模型表明，从挖出到侵入抗力较低的沉积岩的过程控制着湿地发展的周期。通过使用宇宙成因同位素分析(CIA)确定基岩穿过辉绿岩侵入体的切割速率，以及通过光激发发光(OSL)确定泛滥平原发育的时间，可以在湿地发育的概念模型中添加长期的年代学约束。模型的改进将增加对南部非洲河流发展的了解，以及对冲积基岩河流以及冲积和基岩过程之间相互作用的理解。南部非洲目前的湿地恢复工作针对的是人类造成退化的原因。如果这些湿地的退化在结构上是地貌性质的，那么管理策略就需要调整。这项研究获得的信息将有助于南非的湿地保护和恢复计划。

0754345Keen-ZebertThe International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four month research fellowship by Dr. Amanda Keen-Zebert to work with Dr. Stephen Tooth at the University of Wales, Aberystwyth in the UK.Wetlands are a focus of conservation efforts worldwide. However, geomorphological wetland research has been limited. In the Highveld of South Africa, the relationship between alluvial and bedrock river processes has consequences on the stability of wetlands that are an important water resource in a subhumid to semiarid area. The researchers in this project are investigating the long term development and sedimentological factors that effect wetland development and stability in South Africa. The researchers are adding a chronological element to a conceptual model of wetland development in the region that suggests that the progression from exhumation to breeching of dolerite intrusions into less resistant sedimentary rock controls the cycle of wetland development. By determining the bedrock incision rates through the dolerite intrusions using cosmogenic isotope analysis (CIA) and the timing of floodplain development through optically stimulated luminescence (OSL), it is possible to add long term chronological constraint to the conceptual model of wetland development. The improvement of the model will increase the understanding of river development in southern Africa, as well as the understanding of alluvial bedrock rivers and the interaction between alluvial and bedrock processes. Current wetland rehabilitation efforts in southern Africa are directed at human causes of degradation. If the degradation of these wetlands is structurally geomorphic in nature, then management strategies need adjustment. The information gained in this study will benefit wetland conservation and rehabilitation programs in South Africa.