长江流域有机碳同位素地球化学特征

The Character of Carbon Isotope Geochemistry of the Changjiang Drainage Basin

1997年 4～ 5月 ,在长江流域采集的土壤、植物和南北支流与主流悬浮颗粒物样品 ,对其进行了有机质δ13 C分析。结果表明 ,南北支流悬浮颗粒物有机质的δ13 C值范围在 - 2 .8%～- 2 .4 % ,而主流的δ13 C值分布在 - 2 .6 4 %～ - 2 .4 5%。南北支流的输入对长江主流不同地段的δ13 C值有着一定的影响 ,并对长江流域不同物源的贡献大小进行了估算。研究显示 :南部支流中悬浮颗粒物有机质的贡献主要来自高等植物 ;北部支流中高等植物的贡献相对降低 ,富含有机质的土壤成了重要来源。

Soils, plants and suspended particulate matter samples were collected during the investigation in the Changjiang drainage basin in the Spring of 1997. All the samples covered the main streams and southern, northern tributaries. A carbon isotope geochemistry study was carried out among the samples. The distribution of carbon isotope of suspended particulate matter samples of the tributaries ranged from -2.8%～-2.4% .The variation of carbon isotope of suspended particulate matter in the main stream was -2.64%～-2.45%.The carbon isotope of suspended particulate matter in the different zones of the mainstream was variable related to the different inputs of the tributaries. A simple model was applied to estimating the contribution of different inputs over the Changjiang drainage. The results show that high plants contribution was dominated in the south tributaries and the role of soil was in a higher rank in the north tributaries.