黄河中下游河水及沉积物花粉分布与传输特征
Spatial distribution and transport characteristics of river and sediment pollen in the middle and lower reaches of the Yellow River
刘德新 1潘燕芳 1何雪莉 2吴朋飞 3马建华 1谷蕾2
作者信息
- 1. 河南大学地理与环境学院,开封 475004;河南大学黄河中下游数字地理技术教育部重点实验室,开封 475004
- 2. 河南大学地理与环境学院,开封 475004
- 3. 河南大学黄河文明与可持续发展研究中心,开封 475001
- 折叠
摘要
厘清河流花粉现代过程是重建流域古环境的基础.尽管学界较早开展了河水花粉研究,但花粉进入河流之后如何传输、受何种动力影响等问题尚不清楚.本文选取黄河中下游干、支流布设采样断面,在丰水期采集河水和沉积物样品开展花粉分析,采用地理探测器等研究方法,探究花粉分布特征及影响因素.结果表明:①不同流域植被组成不同,花粉类型百分比和浓度存在较大差异,河水干流花粉浓度大于支流,而沉积物花粉百分含量与浓度干流普遍低于支流.②悬浮物浓度是影响河水花粉含量的主要因素,且在晋陕峡谷之外的样点表现尤为突出;粗沙多、流速快可能是导致晋陕峡谷干流悬浮物浓度高而花粉浓度低的原因.③黏粒含量是影响沉积物花粉含量的主要因素,且黏粒分别和粉砂、流速交互作用的影响更为突出;黄河出晋陕峡谷后沉积物花粉含量明显增加.④水库前后河水和沉积物花粉浓度变化分别与悬浮物和黏粒一致,相较于水样,水库后沉积物花粉浓度减少更为明显.⑤河流花粉与表土花粉有良好的对应关系,能较好的反映流域整体植被面貌.研究结果可为利用冲积物或者有河流注入的湖泊花粉开展古环境重建提供支撑.
Abstract
Clarifying the modern process of alluvial pollen is the foundation for reconstructing the ancient environment of the watershed.Although research on the transport of pollen in rivers has started early both domestically and internationally,further research is needed on how pollen is transported and what factors affect it after entering rivers.This paper selects sampling sections for the main stream and tributaries of the middle and lower reaches of the Yellow River,collects river water and sediment samples during the flood season for pollen analysis,and uses methods such as geographic detectors to explore the distribution characteristics and influencing factors of pollen.The results show that:(1)The vegetation composition varies in different watersheds,and there are significant differences in the percentage and concentration of pollen types.The pollen concentration in the main stream of river water is higher than that in the tributaries,while the percentage and concentration of sediment pollen in the main stream are generally lower than those in the tributaries.(2)The concentration of suspended solids is the main factor affecting the concentration of pollen in the Yellow River,and it is particularly prominent outside the Shanxi-Shaanxi Gorge.Furthermore,excessive coarse sand and rapid flow velocity may be the reasons for the high concentration of suspended solids and low concentration of pollen in the main stream of the Shanxi-Shaanxi Gorge.(3)The sediment clay content is the main factor affecting the pollen content of sediment,and the interaction between clay and silt,clay and flow velocity is more prominent.After the Yellow River exited the Shanxi-Shaanxi Gorge,the concentration of sediment pollen and clay particles significantly increased.(4)The changes in pollen concentration in the river water before and after the reservoir are consistent with those in suspended solids,while the changes in sediment pollen concentration are consistent with those in clay particles.Compared to water samples,the decrease in pollen concentration in sediment after the reservoir is more pronounced.(5)There is a good correspondence between river pollen and topsoil pollen,which can better reflect the overall vegetation landscape of the watershed.The results can provide support for paleoenvironmental reconstruction using alluvial deposits or lake sediment pollen injected by rivers.
关键词
河水花粉/沉积物花粉/空间分布/传输机制/黄河中下游Key words
river pollen/sediment pollen/spatial distribution/transmission mechanism/the middle and lower reaches of the Yellow River引用本文复制引用
基金项目
国家自然科学基金(41907382)
中国博士后科学基金(2019M652520)
河南省博士后科学基金(201902025)
出版年
2024
NETL
NSTL
万方数据