对采集衡阳盆地松木剖面的红粘土进行了ESR定年和元素、碳氧稳定同位素测试分析,结果表明:松木剖面delta~(13)C曲线和delta~(18)O曲线的相位和形状基本相同。碳氧同位素曲线图显示,1.78Ma B. P. ~ 1.56Ma B. P.期间,碳氧同位素偏轻,为温暖湿润气候; 1.56MaB. P. ~ 0.716MaB. P.时期,碳氧同位素稍偏重,指示为冷干气候; 0.716Ma B. P.以后,碳氧同位素偏重,干冷程度比上阶段增强。松木红土剖面delta~(13)C曲线和段家坡黄土剖面delta~(13)C曲线在频率和变化趋势方面相近似,记录了构造尺度上三次气候环境变化,早更新世晚期以来衡阳盆地古气候朝着干冷方向发展,与全球气候波动模式基本一致。
英文摘要:
The results of ESR dating,elemental analysis,carbon and oxygen isotopes analysis of the red earth from Songmu profile in Hengyang basin indicate that the phases and shapes of delta~(13)C curve and delta~(18)O curve are basically the same. Carbon oxygen isotopes charts display that during the period of 1.78 Ma B. P. ~ 1.56Ma B. P.,carbon and oxygen isotopes are underweight,it belonged to warm and humid climate; during 1.56 Ma B. P. ~ 0.716Ma B. P.,carbon and oxygen isotopes are slightly overweight and indicating dry and cold climate; after 0.716Ma B. P.,carbon and oxygen isotopes are overweight,indicating the degree of dry and cold were strengthened. The phases and shapes of delta~(13)C curve both Songmu red earth profile and Duanjiapo loess profile are basically the same,which recorded three climate environment change in tectonic scales. The two delta~(13)C curves consistently showed the paleoclimate was becoming drier and colder in Hengyang basin since the late Early Pleistocene, that was basically the same with the global climate fluctuation patterns.