Federal University, Gusau, Zamfara State, Nigeria.
University of Medical Sciences, Ondo, Ondo State, Nigeria.
Environ Monit Assess. 2021 Oct 18;193(11):729. doi: 10.1007/s10661-021-09533-w.
The study determines the textural characteristics and geochemical composition of the transgressive mud coastal marine sediments of the Bight of Benin, Nigeria. The sediment samples were collected using a VanVeen grab sampler from three onshore and three offshore locations. The particle size analysis was conducted with a combination of the pipette sampling and wet sieving of the fraction > 62-µm method, while the concentrations of major oxides were determined by employing X-ray fluorescence technique. The onshore and offshore sediment samples were composed of 54% silt and 30% sand (sandy silt) and 45% sand and 31% clay (clayey sand), respectively. The sequence of concentrations of major oxides was SiO > CaO > AlO > FeO > NaO > MgO > KO > TiO > PO > MnO. Chemical classification scheme of the sediment sampled was Fe-shale. The range of SiO/AlO and KO/NaO ratios of the onshore sites was 5.59-6.74 and 0.31-0.32, respectively, while of the offshore site was 6.19-6.99 and 0.32-0.46, respectively, indicating a low-to-moderate sediment recycling. KO/AlO ratios were low across the sampling sites suggesting abundance of aluminosilicates. The values of weathering indices consisting of Plagioclase Index of Alteration (PIA), Index of Composition Variations (ICV), Chemical Index of Weathering (CIW), and Chemical Index of Alteration (CIA) were similar and varying from low to moderate. Principal component factor analysis (PCFA) extracted three factors for onshore and offshore data with factor loading of clay with MnO, KO, and FeO contents in the offshore sediments while onshore were loaded with CaO, MnO, AlO, and FeO with sand. Geochemical characteristic signified a mixed nature of provenance of both terrigenous and lithogenous sources for onshore and offshore sites respectively.
该研究确定了尼日利亚贝宁湾进积泥质沿海海洋沉积物的结构特征和地球化学组成。使用 VanVeen 抓斗采样器从三个陆上和三个海上地点采集沉积物样品。粒度分析采用组合的移液管采样和 62-μm 以上部分的湿筛法进行，而主要氧化物的浓度则采用 X 射线荧光技术确定。陆上和海上沉积物样品分别由 54%的粉砂和 30%的砂（砂质粉砂）和 45%的砂和 31%的粘土（粘质砂）组成。主要氧化物浓度的顺序为 SiO > CaO > AlO > FeO > NaO > MgO > KO > TiO > PO > MnO。采样沉积物的化学分类方案为 Fe 页岩。陆上站点的 SiO/AlO 和 KO/NaO 比值范围分别为 5.59-6.74 和 0.31-0.32，而海上站点的范围分别为 6.19-6.99 和 0.32-0.46，表明低至中等程度的沉积物再循环。整个采样点的 KO/AlO 比值均较低，表明富含铝硅酸盐。风化指数（包括斜长石蚀变指数（PIA）、成分变化指数（ICV）、风化化学指数（CIW）和蚀变化学指数（CIA））的值相似，从低到中等变化。主成分因子分析（PCFA）从陆上和海上数据中提取了三个因子，其中海上沉积物的因子负荷为 MnO、KO 和 FeO 含量的粘土，而陆上沉积物的因子负荷为 CaO、MnO、AlO 和 FeO 含量的砂。地球化学特征表明，陆上和海上站点的物源分别具有陆源和生源的混合性质。
