川东北石笋120～103ka BP稳定碳同位素记录与控制机制

A Speleothem δ^(13)C Record and Control Mechanism During 120～103ka B.P. from NE Sichuan,Central China

利用川东北梭子洞石笋SZ2的稳定碳同位素组成(δ^(13)C)高分辨率重建了120~103ka时段的石笋碳同位素序列。SZ2的δ^(13)C变化与该石笋稳定氧同位素组成(δ^(18)O)的长期变化趋势明显不同。在整体变化趋势上δ^(13)C变化与生长速率相似,反映石笋表面滴水时间间隔影响的CO_2脱气作用和CaCO_3沉积可能是影响SZ2的δ^(13)C长时间尺度上变化的主要因素。但在较短时间尺度上,SZ2的δ^(13)C与δ^(18)O变化基本趋势一致,反映了地表植被类型(如C3/C4植被比例)、植被密度、土壤微生物活动以及洞穴通风效应的变化可能是引起SZ2的δ^(13)C短时间尺度上变化的主要因素。

A stalagmite（SZ2） collected from Suozi Cave in NE Sichuan, China, established with δ13C data, provides a high-resolution spleothem δ13C time series during 120-103ka. The SZ2 δ13C record appeared to be significantly different from the long-term change trend of the δ13O record. The δ13C record and growth rate of SZ2 show the consistency in the whole trend, which mainly reflected that CO2 degassing and carbonate sediment influenced by drip rates over a speleothem surface influence the SZ2 δ13C record on the long-time scale. On a short time scale, the SZ2 δ13C record appeared to be consistent with the change trend of the δ13O record. The SZ2 δ13C record may be mainly influeneed by vegetation above the cave（proportion of C3 to C4 plant）, density of vegetation, soil microbial activity and cave ventilation.