巴丹吉林沙漠东南缘砂楔年代及其环境意义  

The age of sand wedges and its environmental significance at the southeast edge of Badain Jaran Desert

作　　者：余莺潇 王乃昂[1] 隆浩[2] 宁凯[1] 孙杰[1] 张律吕 

机构地区：[1]兰州大学资源环境学院,兰州730000 [2]中国科学院南京地理与湖泊研究所,南京210000

出　　处：《科学通报》2017年第30期3461-3469,共9页Chinese Science Bulletin

基　　金：国家自然科学基金(41530745;41371114)资助

摘　　要：巴丹吉林沙漠东南缘新近发现的多处砂楔群和融冻褶皱,分别形成于砂砾石层和湖相沉积地层中,楔内充填物的光释光年龄证明其是末次冰期和晚冰期的产物.巴丹吉林沙漠在末次冰期和晚冰期时处于多年冻土带,年平均气温约为-3^-6℃,较现在降温约12~15℃.其时,整个阿拉善高原与纬度多年冻土带和青藏高原冻土区相连接,沙漠腹地及周边的沙丘应处于冻土状态,沙丘的移动和风沙地貌发育均会受到影响.在冷期,巴丹吉林沙漠很有可能相当于冰冻圈气候,前人关于中国北方沙漠非冻土区的认识值得商榷.Sand wedge is a product of permafrost in cold climate, and it is of great significance to restore paleoclimate and paleoenvironment. Since the early 20th century, periglacial landforms such as sand, ice, and soil wedges and glacial mud have been intensively studied in North America, Europe, and Russia. Nevertheless, the distribution of desert areas in the permafrost regions after the last glacial period is still debated in academia. Particularly, in China, it has been argued that desert areas were not the parts of ancient permafrost regions. Moreover, the studies of ancient sand wedges are mostly limited to the last glacial period. In recent years, several groups of ancient sand wedges and glacial mud have been recognized in the Badain Jaran Desert. This filled the gap in the Chinese literature regarding ancient permafrost and proved that desert region belonged to the scope of permafrost regions during the last glacial period. The newly discovered sand wedges in the southeast Badain Jaran Desert comprise sand and gravel layers. Optically stimulated luminescence dating of the filler in the sand wedges suggests that they formed during the last glacial period and the late glacial maximum, in particular. The annual average temperatures in the Badain Jaran Desert during the last glacial period were approximately -3-6℃, and it is 12-15℃ cooler than present. The filler in sand wedges was mainly poorly sorted fine sand that was not transported from afar but from nearby sand dunes. According to the sand wedge groups of the last glacial period in the desert and seasonal frozen soil, we can infer that the Badain Jaran Desert was a part of the permafrost that may have been continuous and widespread. The extent and distribution of the Badain Jaran Desert in the last glacial period was probably different than today, reflecting the dynamic nature of sand dunes. According to the law of sand dunes＇ movement in the Badain Jaran Desert, combining with the characteristics of aeolian sand of the desert＇s ancient permafrost we

关 键 词：砂楔 末次冰期 晚冰期 多年冻土 巴丹吉林沙漠 冰冻圈 

分 类 号：P53[天文地球—古生物学与地层学] P931[天文地球—地质学]