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对我国河西走廊东端西北内陆干旱区与东部季风区交汇带的石羊河流域三角城古湖泊剖面进行了有机质碳同位素组成、有机碳和碳酸盐含量分析 ,重建了西北干旱区全新世古气候高分辨变化模式。分析结果表明有机质碳同位素组成能灵敏地反映该区湖相地层记录的古气候特征 ,是一个较好的古气候替代指标。在温湿期 ,湖泊水体扩大 ,生产力高 ,沉积物中有机质主要是沉水植物供给 ,δ1 3Corg偏重 ;在干冷期 ,湖泊水体减小 ,沉积物中有机质以挺水植物为主 ,植被不发育 ,沉积物中有机质含量低 ,δ1 3Corg偏轻。全新世气候演化主要分为 4个主要阶段 :暖湿期(约 10 0 0 0～ 5 0 0 0 a B.P.)、温湿期 (约 5 0 0 0～ 3 80 0 a B.P.)、凉湿期 (约 3 80 0～ 2 6 0 0 a B.P.)、干旱期 (约 2 6 0 0 a B.P.至今 ) ,各阶段中气候快速变化明显。该区的古气候演化与同处于我国东部季风西北边缘的相邻地区有一定的可比性 ,也具有自身的区域特色。
The carbon isotope composition, organic carbon and carbonate content of organic matter in the triangular lakes of the Shiyang River basin in the confluence of the inland northwest arid region and the eastern monsoon region at the eastern end of the Hexi Corridor were analyzed. The Holocene High-resolution climate change patterns. The analysis results indicate that the organic carbon isotope composition can sensitively reflect the paleoclimate recorded by the lacustrine strata in this area, which is a good indicator of paleoclimate replacement. During the warm and humid periods, the water bodies in the lake expanded and the productivity was high. The organic matter in the sediment was mainly supplied by the submerged macrophytes, and the δ1 3Corg was heavier. During the dry and cold periods, the water bodies in the lake decreased, and the organic matter in the sediments was mainly emergent plants. , Low organic matter content in sediments, δ1 3Corg partial light. The Holocene climatic evolution is mainly divided into four main stages: Warm-humid period (about 10 0 0 ~ 5 0 0 0 0 a BP), Warm-humid period (about 5 0 0 0 ~ 3 80 0 a BP), cool-wet period (About 3 80 0 ~ 2600 a BP) and drought period (about 2600 a BP so far), the climate in each stage has obvious rapid changes. The palaeoclimate evolution in this area has certain comparability with the adjacent areas in the northwest edge of monsoon in eastern China, and also has its own regional characteristics.