论文部分内容阅读
对北京房山东甘地8．2m的剖面取样197块，进行高分辨率的孢粉分析和序列的~(14)C测年，对照烧失量测定、炭片统计、表土花粉和古地磁特征等分析，揭示了北京房山里今16000－7000年植被演替及环境变迁的六个阶段、约15780－14700aB．P，当时乔木稀疏，草本类以蒿、藜为优势，由于缺乏水生沼生植物，反映研究区气候干旱。约14700－13400aB．P，由于降雨增多，温度增大，平原区形成小的沼泽环境，水生植物繁盛，泥炭发育。但区域性针阀混交林中主要以寒湿性针叶树种为主，反映寒冷湿润的气候特征。在14060－13520aB．P．泥炭积累中断，为一干冷的气候突变期。约13400－12600aB．P，针阀混交林在山区又进一步发展，平原区水生植物减少，沼泽逐渐疏干，反映气候趋于暖干。约12600－11400aB．P，针阀混交林中呈现以针、阔叶树种交替占优势的现象。水生、湿生植物减少，反映气候有冷暖的波动。约11400－9600aB．P，植被稀疏。在10600－10300aB．P，出现了与新仙女木期时段相当的冷干气候。约9600－7000aBP，阔叶树种增加，反映由典型草原向森林草原的演替，水生植物不繁盛，气候由冷干向温暖转变。
A total of 197 samples were collected from a 8.2 m section of Fangshan, Gandhi, Beijing. The results of high-resolution sporopollen analysis and sequence analysis of ~ (14) C, determination of control loss, carbon statistics, topsoil pollen and paleomagnetic features Analyzed and revealed six phases of vegetation succession and environmental change in Fangshan, Beijing between 16000 and 7000, about 15780-14700aB. P, sparse trees at that time, herbs to Artemisia, quinoa as the dominant, due to the lack of aquatic macrophytes, reflecting the study area climate arid. About 14700-13400aB. P, As the rainfall increases, the temperature increases, a small swamp environment formed in the plains, aquatic plants prosperous, peat development. However, mainly in the needle-valve mixed forest of alpine cold-temperate conifer species, reflecting the cold and humid climate characteristics. At 14060-13520aB. P. Peat accumulation of disruption, a dry climate change period. About 13400-12600aB. P, needle mixed forest in the mountains and further development of the plains area of aquatic plants to reduce the swamp dredging, reflecting the climate tends to warm dry. About 12600-11400aB. P, acupuncture mixed forest needle, broad-leaved trees alternate dominant phenomenon. Aquatic, wet plants reduced, reflecting the warm and cold climate fluctuations. About 11400-9600aB. P, sparse vegetation. At 10600-10300aB. P, appeared with the new fairy wood period quite dry climate. About 9600-7000aBP, broad-leaved species increased, reflecting the succession of typical steppe to the forest steppe, aquatic plants are not prosperous, the climate changes from cold to warm.