International Research Fellowship Program: Sediment Transport in Marine Environments: Processes, Timescales, and Paleoclimatic Implications

该奖项由2009年美国复苏和再投资法案(公法111-5)资助。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至24个月的研究。该计划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。该奖项将支持维多利亚·E·李博士与英国牛津大学的吉迪恩·M·亨德森博士合作的为期24个月的研究奖学金。该项目的目的是确定海洋沉积物形成和演化所涉及的时间尺度和过程。这一信息对于准确解释海洋沉积物中的古气候和古海洋替代记录是必要的。特别令人感兴趣的是深海漂流沉积物的代理记录。细粒沉积物向漂流的侧向平流导致高沉积速率，这对于高分辨率古气候研究是可取的。然而，这一过程也可能导致与不同粒度相关联的代理的空间和时间去耦合？深海洋流对细粒沉积物的横向平流可以将记录非局部环境条件的较老的代用品输送到给定的沉积地点。因此，要破译一个特定的位置？S古记录需要有关细粒沉积物组分的运移历史的信息。国际冰川协会正在调查冰川-间冰期海平面变化对百慕大隆起沉积物运移历史的影响，百慕大隆起沉积物构成了一个具有重要古气候意义的深海漂移地点。这是通过应用一套相对较新的地球化学工具来完成的，这些工具是：铀系列粉碎年龄法、用于确定沉积物聚焦系数的过量钍-230、光激发发光测年和化合物特定碳14测年，以及用于来源的常规钕和锶同位素。通过进行这些测量获得的信息的总和将提供定量的海洋沉积物运输和储存时间表，洞察相关的漂流形成过程，并更好地理解如何解释多代理古气候记录。这直接关系到对当前社会关注的地球--S气候系统的认识。

0853110LeeThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The 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. Victoria E. Lee to work with Dr. Gideon M. Henderson at Oxford University in the United Kingdom.The aim of this project is to determine the timescales and processes involved in the formation and evolution of marine sediment deposits. This information is necessary for accurate interpretation of the paleoclimatic and paleoceanographic proxy records hosted in marine sediments. Of particular interest are proxy records in deep-sea drift deposits. Lateral advection of fine-grained sediment to drifts causes high sedimentation rates that are desirable for high-resolution paleoclimate studies. However, this process can also cause spatial and temporal decoupling of proxies associated with different grain sizes ? lateral advection of fine-grained sediment by deep ocean currents can transport older proxies recording non-local environmental conditions to a given depositional site. Therefore, deciphering a given location?s paleoproxy record requires information about the transport history of the fine-grained sediment fraction. The PI is investigating the effects of glacial-interglacial sea level changes on the transport history of the Bermuda Rise sediments, which comprise a deep-sea drift site of paleoclimatic importance. This is being done by applying a suite of relatively new geochemical tools, which are: the uranium-series comminution age method, excess thorium-230 for determining sediment focusing factors, optically stimulated luminescence dating, and compound-specific carbon-14 dating, as well as conventional neodymium and strontium isotopes for provenance. The sum of the information obtained by conducting these measurements will provide quantitative marine sediment transport and storage timescales, insight into the related drift-forming processes, and a better understanding of how to interpret multiproxy paleoclimate records. This has direct relevance for understanding the Earth?s climate system, which presently is of societal concern.