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呼伦贝尔沙地保存的风沙层-古土壤沉积序列,是认识过去环境变化的重要地质记录。沙地沉积具有速率快、沉积与侵蚀并存的特点,因此,通过大量独立的光释光年代控制对不同的剖面进行拼接,可以重建沙地在千年尺度上干湿变化过程以及特征时期的边界。本文获得了呼伦贝尔沙地8个沉积剖面的47个光释光年代和近200个样品的环境代用指标数据,结合已发表文献资料,揭示了16ka以来呼伦贝尔沙地千年尺度的干湿变化,并估算了末次盛冰期(LGM)和全新世大暖期(HO)沙地流沙的边界。初步认为,LGM期间,呼伦贝尔沙地相对于现代沙带边界,最远向北移动了约60km,向东移动了约50km,并且南北沙带之间的区域全部沙化;LGM期间沙漠化面积达到22337km~2,相对现代沙漠化面积扩大了约2.7倍。而在HO期间,整个沙地被植被所固定,发育砂质古土壤层,只在局部区域存在短暂的风沙活动。
The sandstorm-paleosol depositional sequence preserved in Hulunbeier Sandy Land is an important geological record for understanding the past environmental changes. Sandy sediments are characterized by high rates of sedimentation and erosion. Therefore, splicing of different sections through a large number of independent photoluminescence dating controls can reconstruct the dry-wet process of the sandy land at the thousand-year scale and the boundary of the eras. In this paper, we obtained the data of environmental substitution for 47 photosolubilization ages and nearly 200 samples of 8 sedimentary sections in Hulunbeier Sandland. Combined with the published literature, the wet and dry changes of the Hulunbeier Sandy millennium scale since 16 ka were revealed and estimated The boundaries of the last glacial (LGM) and Holocene (HO) sand quicksands. It is preliminarily believed that during the LGM, the Hulunbuir sandy land moved as far as 60km to the north and 50km to the east relative to the modern belt boundary, and the area between the north and south sand belts was completely desertified. The area of desertification during the LGM reached 22,337km ~ 2, Relatively modern desertification area has expanded about 2.7 times. During the HO period, the whole sandy land was fixed by vegetation, and the sandy paleosol layer was developed. There was only brief sand blown sand movement in some areas.