论文部分内容阅读
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。
The stalagmite carbon isotope sequences of the stalagmite were reconstructed from the stably carbon isotopic composition (δ ~ (13) C) of the stalagmite SZ2 in the northeast Sichuan Basin. The change of δ ~ (13) C of SZ2 and the stable oxygen isotope composition (δ ~ (18) O) of this stalagmite are obviously different from each other. The changes of δ ~ (13) C are similar to the growth rates in the trend of overall variation. The de-aeration of CO_2 and the deposition of CaCO_3, which reflect the effect of drip irrigation interval on stalagmite surface, may be the main factors that affect the long time scale variation of δ ~ (13) C in SZ2 factor. However, on a relatively short time scale, δ ~ (13) C and δ ~ (18) O of SZ2 are basically the same, reflecting the correlation between the types of surface vegetation (such as the ratio of C3 / C4 vegetation), vegetation density, soil microbial activity, The change of ventilation effect may be the main factor that causes the short time scale change of δ ~ (13) C of SZ2.