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。
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.
作者
刘德新
潘燕芳
何雪莉
吴朋飞
马建华
谷蕾
LIU Dexin;PAN Yanfang;HE Xueli;WU Pengfei;MA Jianhua;GU Lei(College of Geography and Environmental Science,Henan University,Kaifeng 475004,Henan,China;Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions,Ministry of Education,Henan University,Kaifeng 475004,Henan,China;Key Research Institute of Yellow River Civilization and Sustainable Development,Henan University,Kaifeng 475001,Henan,China)
出处
《地理学报》
EI
CSSCI
CSCD
北大核心
2024年第5期1246-1264,共19页
Acta Geographica Sinica
基金
国家自然科学基金项目(41907382)
中国博士后科学基金项目(2019M652520)
河南省博士后科学基金项目(201902025)。
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
river pollen
sediment pollen
spatial distribution
transmission mechanism
the middle and lower reaches of the Yellow River
