摘要
通过对云南寻甸白石岩仙人洞1号石笋(XR1)进行TIMS-U系测年和氧碳同位素分析,揭示了该区全新世中期氧碳同位素气候演化的模式。依据石笋不同时段有机碳含量的变化,重建了基于石笋有机碳指标的气候变化模式。通过对比,发现这两种指标所记录的寻甸地区古气候变化过程几乎完全一致。云南寻甸地区全新世中期的气候演化可分为3个气候期:1)8 000—5 600 aBP为温暖湿润期,气温较高,降水丰沛,石笋的氧碳同位素偏负,有机碳含量偏高;2)5600—4500 aBP为气候突变期,气候由温湿变为冷干,石笋氧碳同位素持续偏正,有机碳含量持续降低;3)4500—2100 aBP为冷干气候期,该期气候稳定,氧同位素和有机碳含量变化不大,均维持在较低水平。
Based on the high precision TIMS-U series dating and the carbon and oxygen isotope record of XR1 stalagmite from Xianrendong cave in Xundian, Yunnan Province, this paper reveals the climate change pattern of the middle Holocene in the study area. According to the organic carbon content change in different periods, we reconstruct the climate change pattern. By comparing the carbon and oxygen isotope records, we discover that both records show the same climate change pattern. Accordingly, the monsoon climate history can be divided into three climate periods in Xundian District during the middle Holoeene. （1） From 8000 a BP to 5600 a BP, it was a warm and wet period, during which, temperature was high and rainfall was abundant. Carbon and oxygen isotopes were lower than the average of the middle Holocene, and the content of organic carbon was higher than the average of the middle Holocene. （2） From 5600 a BP to 4500 a BP, there was an abrupt climate change changing from warm and wet to cold and dry. The carbon and oxygen isotopes became higher, and the content of organic carbon became lower. （3） From 4500 a BP to 2100 a BP, it was a cool and dry climate period, during which the climate was stable and temperature rose slowly. The value of oxygen isotope and organic carbon content change a little, and it was lower than the average of the middle Holocene.
出处
《热带地理》
北大核心
2009年第6期515-519,538,共6页
Tropical Geography
基金
中国科学院创新课题(kzcx2-yw-318)
国家自然科学基金课题(40830852)
973课题(2007CB815905)
ARC课题(DP0773081)
关键词
XR1石笋
中全新世
氧碳同位素
有机碳
XR1 stalagmite
the middle Holocene
oxygen-carbon isotope
organic carbon
