摘要
本文用数字滤波方法,对昆明盆地1号孔的孢粉时间序列进行了波动特征的研究。结果表明,植物演变存在着四种显著的周期,分别为:大于100万年的长周期,25-31万年的中等周期,9.7-12.5万年及4.8-6.3万年的短周期。“三通”(低通、带通、高通)滤波曲线显示了植被演变阶段和演变模式的信息,展现出地质断代特征。本文还将三通滤波曲线与气候波动、深海氧同位素及地球轨道偏心率曲线加以对比,可比性很好。在定量分析计算的基础上,应用古植被古气候分析和测年成果对昆明缸地第四纪气候变化的周期性进行了讨论,并建立了第四纪气候变化序列。
The low-pass,band-pass and high-pass digital filtering methods were adopted to study the periodical fluctuations of vegetation in accordance with the pollen spore series of No.1 bore- hole in Kunming Basin.The result showed that there were obviously 4 periods in vegetation succession:the long period was 1—1.4 million years;the middle period was 0.25—0.31 mil- lion years;the short period was 97—12 and 48—63 thousandyears.The three-pass filtering curves showed the information of geological dating,stage and pattern of vegetation succession. This paper presents a good contrast with the three-pass filtering curves,climatic fluctua- tion,O isotope in deep sea and the earth's orbit eccentricity.The result is satisfactory.The paleoclimatic analysis and the geological dating methods,based on the quantitative analysis,are used to discuss the paleovegetation succession,stage and pattern as well as the fluctuation of the pollen time series and the climate cyclic variation and to present the succession of the climatic variation in the Quaternary.The succession contains two climatic cycles,each for more than 1 million yrs.,ten climatic periods,each for 0.25—0.3 million yrs.,and 25 climatic fluctuations, each for 97—125 thousand yrs. It is considered that the geological and climatic information can be validly extracted by means of the method of the digital filtering from the pollen spore succession;thereupon we may deduce the succesional trend and progress of the paleovegetation that reflects the flutua- tions of the paleoclimate and the geographical conditions.
关键词
第四纪
孢粉时间序列
古环境
Quaternary
Pollen-spore time series
Paleoenvironment
Digital filtering
