Grain size analysis of sediments from deep Lake Malawi

马拉维深湖沉积物的粒度分析

• 批准号: 21583617
• 负责人: Professor Dr. Frank Sirocko
• 金额: --
• 依托单位: Institut für Geowissenschaften
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2006-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/21583617?language=en
• 关键词: Grain; size; analysis; sediments; deep

We propose to study the Holocene and last glacial sections of a well dated piston core from lake Malawi. This will be done by high resolution digital image analysis (sample width of 300 (m) of thin sections, based on the RADIUS method developed by Seelos & Sirocko, 2005. The Malawi sediments are partly laminated with an average sedimentation rate of 0.33 mm/yr. Thus the grain size record will have annual resolution, and allow to detect the history of eolian dust deflation and riverine flash floods, presenting an annual resolution time series of climate change in equatorial Africa for the last 25.000 years, in particular evaluating the low latitude climate during northern hemisphere cold events like the Little Ice age, the 8.2 ka event, Younger Dryas and Heinrich Events. This work is also a methodological study, because we will have to develop a new RADIUS algorithm for the very fine grained sediments of large lakes. When this algorithm is developed successfully in the first year of the project, the study can be continued further into the past on the ICDP Malawi sediments, but be also applied to other ICDP cores from deep lakes.

我们建议研究全新世和末次冰期部分的一个很好的活塞从马拉维湖的核心。这将通过高分辨率数字图像分析（薄切片的样品宽度为300（m），基于Seelos & Sirocko，2005年开发的RADIUS方法）完成。马拉维沉积物部分为层状，平均沉积速率为0.33 mm/年。因此，粒度记录将具有年度分辨率，并允许检测风成尘放气和河流山洪暴发的历史，提供过去25.000年赤道非洲气候变化的年度分辨率时间序列，特别是评估北方半球冷事件（如小冰期、8.2 ka事件、新仙女木事件和海因里希事件）期间的低纬度气候。这项工作也是一个方法学研究，因为我们将不得不开发一个新的RADIUS算法的非常细粒度的沉积物的大型湖泊。当该算法在项目的第一年成功开发时，该研究可以继续深入到过去的ICDP马拉维沉积物，但也可以应用于其他ICDP深湖岩心。