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贺兰山中段西侧沙漠戈壁沉积发育,生态环境脆弱,对探讨末次冰期以来气候变化与沉积响应具有重要意义.选择了腾格里沙漠东缘晚更新世晚期以来的洪积物剖面进行了初步古环境研究.在数字填图系统和野外路线调查基础上,对贺兰山中段西侧、腾格里沙漠东缘地貌第四纪沉积物进行了较详细的调查研究.在AMS~(14)C测年基础上,从内蒙古阿拉善高原腰坝地区Qp_3-Qh~(pl)洪积剖面沉积物中获得较丰富的植硅体化石,主要类型有方型、长方型、扇型、哑铃型、齿型、帽型、尖型、平滑棒型、刺边棒型、突起棒型、三棱柱型等.此外,沉积物中赋存的大量炭屑和燃烧植硅体反映了古人类活动的历史.运用植硅体组合和温暖指数分析重建了研究区26ka来的古植被、古气候演化,气候变化自早至晚经历了明显的干凉-暖干-暖湿-冷湿-干冷-暖干-暖湿7个阶段.洪积扇扇缘沉积环境变化反映了气候的干湿变化,且气候干湿变化与区域沙漠化和人类活动具有相关性.
The deposition of the desert Gobi in the west of Helan Mountain and its fragile ecological environment are of great significance for the study of climate change and sedimentary response since the last glacial period.Selected the alluvial profile since the Late Pleistocene in the eastern margin of Tengger Desert Based on the digital mapping system and field survey, the Quaternary sediments of the eastern edge of the middle of the Helan Mountains and the eastern margin of the Tengger Desert were studied in detail. AMS ~ (14) Based on the dating of Qp_3-Qh ~ (pl) in the Lhasa area of the Alashan Plateau in Inner Mongolia, the main types of phyllosilicate fossils are square, rectangular, fan-shaped and dumbbell Type, tooth type, hat type, pointed type, smooth rod type, piercing rod type, protruding rod type, triangular prism type, etc. In addition, a large amount of carbon deposit and burned silicon body in the sediments reflect the ancient human activities The ancient vegetation from 26 ka in the study area was reconstructed using the phytolith assemblage and warm index analysis. The paleoclimate evolution of the study area has experienced obvious dry-warm-warm-wet-cold-wet-dry-cold- Warm dry - warm and humid 7 stages of alluvial fan margin depositional environment Reflecting the change of wet and dry climate, and wet and dry climate change and regional desertification and human activities are relevant.