青藏高原东北部共和盆地风成沉积地球化学特征及其揭示的气候变化  

Geochemical Characteristics of Aeolian Deposits in Gonghe Basin,Northeastern Qinghai-Tibetan Plateau and the Indicating Climatic Changes

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：《地球科学进展》2012年第7期788-799,共12页Advances in Earth Science

基　　金：国家自然科学基金项目"晚第四纪以来中国季风区西北缘沙漠演化及其对全球变化的响应"(编号:40971005)资助

摘　　要：通过对共和盆地东部风成沉积的地球化学分析,并结合14C和OSL年代,重建了区域末次盛冰期以来气候变化过程。21 ka BP之前气候寒冷偏湿,21～15.82 ka BP为末次盛冰期(LastGlacial Maximum,LGM),气候极为寒冷干燥;15.82～9.5 ka BP气候转暖且偏干,其中14.5～13.6ka BP和11.9～9.5 ka BP气候明显冷干,分别为老仙女木时期(Oldest Dryas,OD)和新仙女木时期(Younger Dryas,YD),而15.82～14.5 ka BP和13.6～11.9 ka BP(BФlling-AllerФd暖期,B/A)相对温暖;9.5～7.2 ka BP暖湿程度明显提高,7.2～5.1 ka BP气候波动频繁,相对冷干和相对暖湿多次更替。5.1～2.7 ka BP暖湿程度基本稳定,之后气候趋于寒冷但湿度明显较大。这些气候变化过程与青藏高原大量的古气候信息记录具有良好的一致性,表明共和盆地气候变化与青藏高原气候变化的高度一致性。The climatic change since the Last Glacial Maximum （LGM） period was reconstructed based on the analysis of geochemical characteristics of the aeolian deposits in Gonghe Basin, northeastern Qinghai-Tibetan Plat- eau, coupled with the 14C and OSL chronology. The cold and wet climate dominated the region before 21 ka BP, and the climate became very cold and dry in 21 - 15.82 ka BP, corresponding to the LGM period. From 15.82 to 9.5 ka BP, the regional climate tended to be warm and dry in general. During this period, the cold and dry condi- tion occurred in 14.5 -13.6 ka BP and 11.9-9.5 ka BP, implying the Oldest Dryas and Younger Dryas phases, while the relatively warm climate was found in 15.82 - 14.5 ka BP and 13.6 - 11.9 ka BP （Bolling-Allercd peri- od, B/A period）. The warm and humid degree obviously increased between 9.5 and 7.2 ka BP, marking the rela- tively warm and wet condition. The cold-dry and warm-humid climate fluctuated in 7.2 - 5.1 ka BP. In 5.1 - 2.7 ka BP, the degree of warm and wet is relatively stable but it tended to be cold with high moisture since 2.7 ka BP. These changes are coincident with the paleoclimatic records in Qinghai-Tibetan Plateau, reflecting higher consisten- cy in climatic change between Gonghe Basin and Qinghai-Tibetan Plateau.

关 键 词：共和盆地 地球化学 风成沉积 末次盛冰期 

分 类 号：P532[天文地球—古生物学与地层学]