塬堡黄土剖面有机质碳同位素的气候记录数据集（全新世）

对甘肃临夏塬堡全新世黄土剖面古土壤有机质碳同位素的分析表明，δ13C变化范围在-28.23‰~-25.19‰之间，平均值为-26.88‰。结合该剖面孢粉以及地层研究结果，观察到在温暖湿润气候期间，δ13C表现为高值，而在干燥寒冷期间，δ13C表现为低值，这较好地反映了该地区全新世气候演化的历史。结合其他研究，认为黄土高原地区全新世地表植被中草本植物C3和C4植物比例的变化是引起土壤有机质δ13C变化的直接原因，由于气候变化引起了地表植被类型的改变，古土壤中有机质δ13C发生了变化。对比塬堡剖面与西安、旬邑剖面土壤有机质的δ13C，观察到西安和旬邑两剖面的δ13C平均值要高于塬堡剖面约5‰左右，这是由于全新世期间两地气候的暖湿程度要高于临夏地区，地表植被中喜暖湿气候的C4植物比例较高，导致土壤有机质δ13C增大。因此δ13C是研究古气候变化的一个较好的手段。

Analyses of carbon isotopes of organic matter in paleosols from the Holocene loess profile of Yuanbao, Linxia, Gansu Province, show that the δ¹³C values range from -28.23‰ to -25.19‰, with an average value of -26.88‰. Combined with the palynological and stratigraphic results of this profile, it is observed that δ¹³C values are high during warm and humid climate periods, and low during dry and cold periods, which well reflects the evolutionary history of Holocene climate in this region. Combined with other studies, it is believed that changes in the ratio of C3 to C4 herbaceous plants in surface vegetation of the Loess Plateau during the Holocene are the direct cause of variations in soil organic matter δ¹³C values. Climate change alters the type of surface vegetation, leading to changes in δ¹³C values of organic matter in paleosols. By comparing the δ¹³C values of soil organic matter from the Yuanbao, Xi'an and Xunyi profiles, it is observed that the average δ¹³C values of the Xi'an and Xunyi profiles are approximately 5‰ higher than that of the Yuanbao profile. This is because the climate in Xi'an and Xunyi was warmer and more humid than that in Linxia during the Holocene, with a higher proportion of C4 plants adapted to warm and humid climates in the surface vegetation, resulting in increased δ¹³C values of soil organic matter. Therefore, δ¹³C is a reliable tool for studying paleoclimate changes.