Grain-size analysis and geochemistry of sediment core GeoB13602-1

Grain-size, terrigenous element and rock magnetic remanence data of Quaternary marine sediments retrieved at the NW African continental margin off Gambia (gravity core GeoB 13602-1, 13°32.71' N, 17°50.96'W) were jointly analyzed by end-member (EM) unmixing methods to distinguish and budget past terrigenous fluxes. We compare and cross-validate the identified single-parameter EM systems and develop a numerical strategy to calculate associated multi-parameter EM properties. One aeolian and two fluvial EMs were found. The aeolian EM is much coarser than the fluvial EMs and is associated with a lower goethite/hematite ratio, a higher relative concentration of magnetite and lower Al/Si and Fe/K ratios. Accumulation rates and grain sizes of the fluvial sediment appear to be primarily constrained by shore distance (i.e., sea-level fluctuations) and to a lesser extent by changes in hinterland precipitation. […]

在几内亚湾西北部非洲大陆边缘（地理坐标：13°32.71' N, 17°50.96'W）采集的第四纪海洋沉积物的粒度、陆源元素和岩石磁剩磁性数据（重力岩心GeoB 13602-1）经端元（EM）混合分析方法联合分析，以区分和计算过去的陆源物质通量。本研究对比并交叉验证了识别出的单一参数EM系统，并制定了一种数值策略以计算相关的多参数EM属性。研究发现了一种风成EM和两种河流EM。风成EM的粒度远大于河流EM，且与较低的赤铁矿/磁赤铁矿比值、较高的磁铁矿相对浓度以及较低的Al/Si和Fe/K比值相关。河流沉积物的累积速率和粒度似乎主要受海岸距离（即海平面波动）的影响，在一定程度上也受内陆降水变化的影响。