山西临汾盆地末次冰期时段湖相沉积中的H、D/O事件记录

THE STUDY ON THE RECORDS OF H AND D/O PALEOCLIMATIC EVENTS DURING THE LAST GLACIAL PERIOD FROM THE LACUSTRINE SEDIMENT IN LINFEN BASIN,SHANXI GRABEN

千伏村剖面是一沉积延续时间跨越末次冰期时期的湖相沉积剖面。论文利用S_1/L_1、L_1/S_0界线年龄及OSL测年数据建立了剖面的深度-年龄坐标系。根据早期形成的分别与气下黄土和古土壤层发育时代对应的、指示不同气候条件下的湖相沉积层特征差异,论文遴选出小于4μm粘土组分含量、中值粒径(Md)、沉积物磁化率、有机质含量、Rb/Sr比值等参数作为区域气候指代参数。剖面系列气候指代参数的变化曲线显示,区域末次冰期期间出现了10个干冷期,发生时间分别在16.9ka B.P.,22.7ka B.P.,24.9ka B.P.,27.1ka B.P.,31.7ka B.P.,41.5ka B.P.,52.8ka B.P.,56.2ka B.P.,61.6ka B.P.和67.5ka B.P.;其中16.9ka B.P.,22.7ka B.P.,27.1ka B.P.,41.5ka B.P.,52.8ka B.P.和67.5ka B.P.可与北大西洋地区的HI^H6干冷期事件对应。剖面系列气候指代参数变化曲线也记录了区域18个暖湿事件,且这些事件可与北大西洋地区的D/O循环间冰阶事件对应。研究结果显示东亚地区末次冰期期间的气候高频波动可能与北大西洋地区存在某种联系。

Qianfucun section （36°4.316′N,111 °37.003′E）,located in the south slope of Ju River in the Yaodu District,Linfen City,is 930cm high,containing lacustrine sediment of 748cm thick.The lacustrine sediment is capped by paleosol So and underlain by paleosol S1,implying it was deposited during the last glacial period.There developed 28 different sub-layers in the lacustrine sediment,which contains plentiful information about the paleoclimatic changes with high-resolution.150 lacustrine samples were taken from the section each at an interval of 5cm.Relying on the ages of the boundaries of paleosol/loess S1/L1 and L1/So,and several OSL dates,the depthages timescale was made for the section.According to the previous studies on the characteristics of different lacustrine sediment layers which deposited during the warm-wet episodes and cold-dry ones respectively,it was found that the component of the grains less than 4μm,the median diameter,the magnetic susceptibility,the component of organic matter,the component of Rb and the component of Sr in the sediment are very sensitive to the paleoclimatic changes,and in the paper these sediment parameters are adopted as paleoclimatic proxies.The curves of these sediment parameters of the section have showed that there exist 10 dry-cold-phases during the last glacial period with the ages of 16.9ka B.P.,22.7ka B.P.,24.9ka B.P.,27.1ka B.P.,31.7ka B.P.,41.5ka B.P.,52.8ka B.P.,56.2ka B.P.,61.6ka B.P.and 67.5ka B.P.respectively,among which the ages of 16.9ka B.P.,22.7ka B.P.,27.1ka B.P.,41.5ka B.P.,52.8ka B.P.and 67.5ka B.P.correspond to those of Heinrich events 1 to 6 occurred in North Atlantic Ocean.The curves of these sediment parameters in the section have also recorded 18 wet-warm-phases which correspond to different D/O cycles in sequences occurred in North Atlantic Ocean.The research results imply that the paleoclimatic changes in North China during the last glacial period may have relations with that in North Atlantic Ocean.