选择青藏高原腹地可可西里地区为研究区,以古地磁测年结果为年代框架,应用轨道调谐方法建立了BDQ06孔的年代标尺。通过对BDQ06孔沉积物粒度、磁化率、总有机碳及色度等指标的分析,重建了可可西里地区0.9Ma以来古气候演化序列。气候演化过程划分为5个阶段:阶段5(929-660ka BP)暖湿和冷干交替变化;阶段4(660-460ka BP)气候向偏冷偏干方向发展;阶段3(460-360ka BP)气候温和偏干;阶段2(360-160ka BP)气候暖湿冷干波动频繁交替;阶段1(160-5ka BP)暖湿冷干组合。同时该区湖泊沉积物环境指标的变化规律和深海氧同位素曲线在冰期-间冰期旋回尺度上有较好的一致性,但也出现不同的变化特征,说明本区既表现出全球一致的气候特征,同时也表现出一定区域特征,可能与青藏高原的构造隆升有关,这对于研究区域气候变化与全球气候变化有着重要的意义。
In this study, Hoh Xil area, hinterland of the Tibetan Plateau, was taken as the research area, tie points derived by matching the observed agnetostratigraphy were adopted to establish the geomagnetic polarity time scale (GPTS) , an orbital tuned timescale was developed for core BDQ06. The climate evolution in Hoh Xil since 0.9MaBP was reconstrcted by analyzing colour, magnetic susceptibility, total organic carbon (TOC), and grain size of lacustrine sediments. Evolutionary process of the climate can be divided into 5 stages : stage 5 (929 660kaBP) : alternating between warm - humid and cold - dry period ; stage 4 (660 - 460kaBP) : climate was temperate and turned dry; stage 3 (460 -360kaBP) :comparatively temperate and arid climate; stage 2 (360 160kaBP) : cold - arid and warm - moist alternated frequently;stage 1 (160 - 5kaBP) :alternating between warm - humid and cold - dry period. Furthermore, the climate change of our study area was compared with the LR04 marine 8180 record. The results indicated that there was very strong similarity with the scale of glacial -interglacial cycle, however there were also obvious regional differences. That is to say, our research area responded to global climate change with regional characteristics, which might be related with the tectonic uplifting of the Tibetan Plateau and had an important significance for studying regional climate change and global climate change.