末次盛冰期以来青藏高原东北部共和盆地冬夏季风演化记录  

The Record of Winter and Summer Monsoon Evolution in Gonghe Basin,Northeastern Qinghai-Tibetan Plateau since the Last Glacial Maximum Period

作　　者：刘冰[1] 靳鹤龄[1] 孙忠[1] 苏志珠[2] 张彩霞[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所沙漠与沙漠化重点实验室,甘肃兰州730000 [2]山西大学历史文化学院,山西太原030006

出　　处：《中国沙漠》2013年第2期433-442,共10页Journal of Desert Research

基　　金：国家自然科学基金项目(40971005和41271215)资助

摘　　要：对青藏高原东北部共和盆地冬其剖面的化学元素与粒度分析表明,末次盛冰期以来区域冬夏季风总体上呈现此消彼长的关系,气候出现多次冷干-暖湿旋回。15.82ka BP之前冬季风最强,夏季风最弱,为末次盛冰期时的冷干气候,但21ka BP之前气候可能寒冷偏湿。15.82～9.5ka BP夏季风明显增强,冬季风衰弱,气候明显转暖,其中老仙女木时期(14.7～13.7aBP)和新仙女木时期(12.1～9.5ka BP)气候相对冷干,而B-A时期(13.7～12.1ka BP)气候相对暖湿。全新世以来冬夏季风出现多次波动,9.5～7.0ka BP夏季风相对较强,气候相对暖湿;7.0～5.1ka BP冬夏季风强弱交替频繁,气候出现冷干-暖湿旋回;5.1～2.7ka BP夏季风总体较强,气候温暖湿润;2.7ka BP之后冬季风明显增强,气候趋于冷干。此外,区域冬夏季风演变过程与极地冰芯记录的冷暖事件大体一致,可以认为共和盆地气候变化是全球气候变化的区域响应。Geochemical and grain size analysis on aeolian deposits in the DQ profile from Gonghe Basin, northeastern Qinghai-Tibetan Plateau, indicated that the characteristics of regional winter and summer mon- soonal variation was that when one was rising, the other was falling, and the climate had experienced several cold-dry and warm-wet cycles since the last glacial maximum （LGM） period. The cold and dry climate dominated the region in LGM period before 15.82 ka BP due to the stronger winter monsoon and weaker summer monsoon, but the climate was relatively cold and wet before 21 ka BP. In 15.82--9.5 ka BP, the summer monsoon strength increased and winter monsoon tended to be weaker, implying an obviously warm climate. During this period, the relatively cold and dry condition appeared in the Oldest Dryas and Younger Dryas with time of 14.7--13.7 ka BP and 12.1--9.5 ka BP respectively, while relatively warm and wet in 13.7-12.1 ka BP （B^lling/AllerCd period）. The winter and summer monsoon strength presented a fre- quent fluctuation in Holocene and the relatively warm and wet emergeed in 9.5--7.0 ka BP due to the high- er summer monsoon intensity. From 7.0 ka BP to 5.1 ka BP, the cycle of cold-dry and warm-wet climate was corresponding to the frequent fluctuation in winter and summer monsoon. The climate became warm and wet in 5.1--2.7 ka BP, accompanied with increased summer monsoon, but it tended to be cold and dry since 2.7 ka BP due to the enhanced winter monsoon strength. In addition, the evolution of regional winter and summer monsoon was coincident with the warm and cold records from the polar ice core. In other words, it indicated that the climatic variation in Gonghe Basin could be considered as a regional response to Global climate change.

关 键 词：末次盛冰期 共和盆地 冬夏季风演化 化学元素 粒度 

分 类 号：P532[天文地球—古生物学与地层学]