Mapping Saharan dust fluxes through the onset and termination of the African Humid Period in a transect of African margin cores

在1万1千年至5千年前的非洲湿润期，北非中部形成了大型湖泊、丰富的巨型动物和众多的人类定居点。从这一时期到过去5000年的干旱状态的转变标志着自末次冰期结束以来最剧烈的区域气候变化之一，但目前可获得的记录对这种转变的时间和突然性存在分歧。这项研究从西北非洲大陆边缘的八个沉积物岩心的南北样带中发展了风沙沉积的记录——一个敏感的大陆干旱和大气环流记录器。这些记录将揭示非洲湿润期的开始和结束是否同步发生，并在整个北非以类似的突然性发生。来自岩心的河流沉积物通量和尘埃粒度数据将为降水和风力的变化提供补充的见解。除了阐明驱动季风地区气候突变的机制外，该项目更广泛的影响还包括为博士后新首席研究员提供支持和指导，让本科生参与研究，以及将项目发现纳入哥伦比亚大学本科地球科学课程和高中课程材料。

During the African Humid Period between 11 and 5 thousand years ago, central North Africa supported large lakes, abundant megafauna and numerous human settlements. The transition from this period to the dry conditions of the last 5 thousand years marks one of the most dramatic regional climate changes since the end of the last glacial period, but currently available records disagree over the timing and abruptness of the transition. This research develops records of wind-blown dust deposition-- a sensitive recorder of continental aridity and atmospheric circulation-- from a north-south transect of eight sediment cores from along the northwest African continental margin. These records will reveal whether the beginning and end of the African Humid Period occurred synchronously and with similar abruptness throughout North Africa. Fluvial sediment fluxes and dust grain size data from the cores will provide complementary insights into changes in precipitation and wind strength. In addition to elucidating the mechanisms driving abrupt climate changes in monsoonal regions, this project's broader impacts include support and mentoring for a new principal investigator in a postdoctoral position, involvement of undergraduate students in research, and adaptation of project findings for inclusion in undergraduate Earth science courses at Columbia University and in high school curricular materials.