北京延庆盆地晚更新世以来的古气候演化:有机碳同位素记录  

Paleoclimatic evolution inferred from organic carbon isotope of lacustrine sediments in the Yanqing basin of Beijing since Late Pleistocene

作　　者：张慧娟 杨桂芳[1] 陈正洪[2] 桑萌 

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]中国气象局气象干部培训学院,北京100081

出　　处：《干旱区资源与环境》2017年第12期92-97,共6页Journal of Arid Land Resources and Environment

基　　金：北京市自然科学基金委项目(8162038);国家自然科学基金专项项目(41320003和41220001)资助

摘　　要：为探讨半干旱与半湿润过渡区晚更新世以来的古气候演化,文中以北京延庆盆地为例,对其阜高营剖面湖相沉积物中有机碳同位素进行了详细分析。结果表明:该剖面的有机碳同位素的变化范围在-26.69‰^-21.35‰之间,均值为-23.98‰。主要表现为:有机质以外源输入为主,暖期偏负;有机质以内源输入为主,冷期偏负。结合粒度、磁化率环境指标,延庆盆地晚更新世以来的环境演变可划分为:56.8~45.6ka,温暖湿润;45.6~29.2ka,温和湿润;29.2~12.8ka,寒冷干燥;12.8ka至今,温凉偏干四个阶段。延庆盆地与全球气候变化基本一致,但也表现出一些局地性特征。The organic carbon isotope（ δ13Corg） in the lacustrine sediments of the Fugaoying profile was used to reconstruct the paleoenvironmental variation since middle Late Pleistocene,in combination with analyses of grain size and magnetic susceptibility. The parameter of δ13Corgvalue in the profile ranges from-26. 69‰ to-21.35‰,with an average value of-23. 98‰. The profile is characterized by the lower δ13Corgvalues over the warmer periods due to the major exogenous input,but with an apparent negative spike in δ13Corgvalues during colder episodes as a result of endogenous contribution. Accordingly,the paleoclimatic evolution of the Yanqing basin since Late Pleistocene can be outlined into four stages. The warm and humid climate occurred from 56. 8 ~45. 6ka,then it changed to mild and humid during 45. 6 ~ 29. 2ka. Between 29. 2 and 12. 8ka,the climate was pretty cold and dry,and became slightly warmer since 12. 8ka. Variations of δ13Corgvalues indicate both comparable and local inference of paleoclimate which merits further investigation.

关 键 词：有机碳同位素 气候演化 晚更新世 湖泊沉积物 延庆盆地 

分 类 号：P534.41[天文地球—古生物学与地层学]