云南鹤庆钻孔揭示的古生产力轨道尺度演化

本文在分析鹤庆古湖泊不同演化阶段烧失量指标变化特点的基础上,采用频谱分析、滤波分析方法,探讨了该湖泊古生产力轨道尺度的演化特征．综合分析结果显示:在整个演化过程中,由于北半球夏季太阳辐射与南半球潜热输出相位关系的不同,导致斜率周期一直强于岁差周期;在987-1552 ka阶段,15 ka、10．7 ka和10 ka为较强周期,其中10 ka、10．7 ka周期是与100 ka周期强化有关的半岁差周期;在湖泊古生产力演化中存在与气候变化相一致的中更新世转型．

The orbital scale evolution of the paleoproductivity reflected by Heqing Core in Yunnan Province

Based on loss on ignition of different parts of Heqing sediment cores, we studied the characteristics of orbital scale evolution of the lake paleoproductivity by using Spectral analysis and Filter methods. It shows that obliquity cycle is stronger than precession cycle in the 2. 78 Ma, due to different phasing relationship between summer insolation in the northern hemisphere and latent heat export in the southern Hemisphere. 15 ka, 10.7 ka and 10 ka are the relatively stronger cycles from 987 ka to 1552 ka, in which 10 ka and 10. 7 ka are semi-precession cycles related to the strengthened 100 ka cycles. Further, there is Mid-Pleistocene Revolution coincident with climatic changes in the evolution of lake paleoproductivity.