中亚则克台黄土剖面记录的末次冰期以来的环境演变

The environmental change records since the Last Glaciation at Zeketai loess section,central Asia

选取位于中亚伊犁盆地中东部的则克台(ZKT)黄土剖面作为研究对象,基于13个光释光年代构建了ZKT剖面的年代框架,利用黄土沉积速率、粒度以及总有机碳含量重建了伊犁地区末次冰期以来的环境演变记录。结果表明:(1)伊犁地区末次冰期以来的气候演化阶段可划分为寒冷期(74.5~60 ka)、温湿期(60~30ka)、寒冷期(30~11.5 ka)以及11.5 ka以来的暖湿期,该气候演化特征与深海氧同位素不同阶段气候特征较为一致;(2)MIS4至MIS1阶段则克台剖面沉积速率呈递减趋势,分别为49 cm·ka^(-1)、32 cm·ka^(-1)、13 cm·ka^(-1)和8 cm·ka^(-1);(3)ZKT剖面代表的伊利地区环境演变特征可与格陵兰冰芯进行良好对比,北大西洋地区的快速气候波动信号在伊犁地区气候记录相对清晰,在时间上呈同步变化。

Based on 13 OSL （optical stimulated luminescence） dating results, accumulation rate, grainsize and TOC （total organic content） in Zeketai loess section in central Asia, an environmental evolutionrecord during the Last Glacial Period was reconstructed. The results indicate that： （1） the climatic changein Ili basin during the last glacial period can be divided into 4 stages, i.e. cold stage （74.5-60 ka）, mildmoist stage （60-30 ka）, cold stage （30-11.5 ka） and warm wet stage （11.5 ka-）, and the climatic changingcharacteristics are consistent with marine oxygen isotope records; （2） since the beginning of Last GlacialPeriod, the loess accumulation rates presented a decreasing trend and are 49 cm·ka^-1 in MIS4 stage, 32 cm·ka^-1 in MIS3 stage, 13 cm·ka^-1 in MIS2 stage and 8 cm·ka^-1, respectively; （3） comparing between ZKT loessenvironmental records and the oxygen isotope records in GRIP ice core, we found that the signals of rapidclimatic fluctuation from north Atlantic region are clearly recorded in ZKT loess records synchronously.