【摘要】 以霍林河下游向海湿地为研究对象,通过对湿地垂直剖面的精细采样,将放射性核素精确计年与孢粉组合特征研究相结合,进行高分辨率剖析。研究结果表明:受沉积环境的影响,不同地表水力梯度与不同地貌单元的孢粉组合特征相差较大。典型剖面孢粉图式、A/C比值与麻黄属花粉丰度分析表明,该区域以草甸草原或草原景观为主,流域大环境以半干旱为特征,局部小环境为水流缓慢或静水沉积环境,并受到风沙的影响。240年以来虽然亦存在短暂的温湿期(1851-1861aA.D.及1890-1920aA.D.),但半干旱的气候特征始终没有改变。对照相邻区域研究成果,本区近代气候具有继承性和相似性。更多还原

【Abstract】 The Xianghai Wetlands Nature Reserve (122°05’-122°31’E, 44°55’-45°09’N) was situated in the western border of the Songnen Plain in Northeast P. R. China. It has been listed in The List of Wetlands of International Importance since 1992 (Ramsar site no. 548) . As downstream freshwater wetlands of the Huolin River, the Xianghai Wetlands, covering an area of 360km2, located at parts of the semi-arid climatic zone and border with the Keerqin Desert. Xianghai Wetlands were located at transition zones of terrestrial and aquatic ecosystems, where they received sediment inputs from both systems. The Huolin River was an interior river and its downstream wetlands were inside a semi - enclosed basin. Therefore, the Xianghai Wetlands might be important reservoirs for fine, upstream coming sediments. Here we reported a case study on the Xianghai marsh wetlands at downstream of an interior river - Huolin River located at semi - arid area. Sediment cores, representing a range of watershed characteristics and anthropogenic impacts, were collected in winter season (to avoid disturbing the sediment layers) from Erbaifangzi marshes at the Xianghai Wetlands in order to trace the historical variation of climate changes and to analyze the pollen combination impacted through sediment samples at different distance away from the main watercourse. By analysis with high resolution of ra-dionuclide timing (210Pb - and 137Cs - dated to age - depth profile translation) and the pollen combination characterization within the typical sedimentation profiles age-spectrum were established. The following results are revealed: The pollen combination characterization was relatively different in different surface water hydraulic gradient and micro landforms unit influenced by sedimentation environment. Through analyzing the pollen graphic formula, the ratio of A/C (Artemisia/Chenopodiaceae) and abundance of Ephedra, the results indicated that the landscape in this area was mainly grassland, macro environment in the catchments was semi - arid and part microenvironment was existed slow water current or still water sedimentation environment and had influenced by karaburan. From 240 years ago to the present, although had existed short period of temperature-humid climate (1851 - 1861aAD and 1890 - 1920aAD), the characterization of semi-arid climate was dominated in whole time. Compared with the research on adjacent area, the modern climate in study area had its succession and similarity.更多还原