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

在11000年前至5000年前的非洲潮湿时期，北非中部支持着大型湖泊、丰富的大型动物和大量的人类住区。从这一时期过渡到过去5000年的干旱条件，标志着自上一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过渡的时间和突然程度存在分歧。这项研究开发了风吹尘埃沉积的记录--大陆干旱和大气环流的灵敏记录--来自非洲西北部大陆边缘的八个沉积物岩芯的南北横断面。这些记录将揭示非洲湿润时期的开始和结束是否在整个北非同步发生，并具有类似的突发性。来自岩心的河流沉积物通量和尘埃粒度数据将提供对降水和风力变化的补充见解。除了阐明季风区气候突然变化的驱动机制外，该项目的更广泛影响还包括支持和指导一名新的博士后首席研究员，本科生参与研究，以及调整项目结果，将其纳入哥伦比亚大学地球科学本科课程和高中课程。

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.