共和盆地开额泥炭剖面粒度敏感组分提取与全新世气候环境变化

采用粒级-标准偏差方法对青藏高原东北部共和盆地全新世KE (开额)泥炭沉积剖面进行了系统的分析,发现63~252 μm (63~112和112~252 μm)的粒度敏感组分可以作为区域冬季风强度变化的替代性指标,并据此重建了全新世共和盆地冬季风演化历史。结果表明:10.0~8.5 cal.kaBP冬季风逐渐减弱,8.5~7.1 cal.kaBP冬季风明显增强,7.1~3.8 cal.kaBP冬季风强度最低,3.8~0.5 cal.kaBP冬季风波动式增强,0.5 cal.kaBP以来冬季风强度迅速降低;对比研究发现,区域冬季风演变历史与青藏高原和中国东部季风区及季风边缘区不同研究载体记录的气候变化过程具有良好的可比性。同时,发现区域全新世7次明显的冬季风增强时期与极地冰心和北大西洋深海沉积记录的寒冷事件具有明显的一致性,可能说明区域气候变化与全球气候变化在动力机制上有着内在的联系。

EXTRACTION OF SENSITIVE GRAIN-SIZE COMPONENT FROM THE KE PEAT DEPOSIT OF THE GONGHE BASIN AND ITS IMPLICATION FOR HOLOCENE CLIMATIC AND ENVIRONMENTAL CHANGE

Grain size versus standard deviation was applied to extract sensitive grain size from the grain size distribution data of the Holocene KE peat deposit of the Gonghe Basin, northeastern Qinghai-Tibetan Plateau. We found that the sensitive grain size component of 63~252 μm(63~112 μm and112~252 μm) can reflect the intensity variation of the regional winter monsoon, upon which we reconstructed the history of the regional winter monsoonal evolution. Our results suggest that the intensity of winter monsoon declined in the period of 10.0~8.5 cal.kaBP, and obviously increased in 8.5~7.1 cal.kaBP. The weakest winter monsoon emerged in 7.1~3.8 cal.kaBP, and it became stronger in the period between 3.8 cal.kaBP and 0.5 cal.kaBP. Afterwards, the winter monsoon rapidly weakened. Comparative study demonstrates that the evolution of regional winter monsoon is correlated well with the climatic change records of the Qinghai-Tibetan Plateau and the marginal monsoonal zone and monsoonal zone in eastern China from different research sources. We also found seven phases of the stronger winter monsoon, which are apparently coincident with the cold events found in the polar ice core and North Atlantic Ocean, probably indicating the inherent relationship of the dynamic mechanism between the regional and the global climatic changes.