- 责任者：Chen Yingyong (Laboratory of Earth Surface Process and Environment ; School of Geographic and Oceanographic Sciences ; Nanjing University ; Nanjing 210093 ; China) ; Lu Huayu
- 刊名：Quaternary Sciences
- 出版年：2013
- 卷期：33(2)
- 关键词：沙地 ; sandy land ; 沉积物 ; sediments ; 全新世 ; Holocene ; 内蒙古 ; Inner Mongolia
- 页码：p.351-359
- 图表：illus., 1 table, 76 refs.
- 分类号：1400
- issnNo：ISSN1001-7410
- isbnNo：CN11-2708/P
composition of surface soil and vegetation-climate is fundamental for reconstruction of past climate change. However,lacking of this kind of study in Otindag dune field, has hindered our understanding of the past environmental changes in this monsoon sensitive region. δ^13C of organic matter could be among the most powerful proxy for reconstructing past vegetation and climate. This study aims to develop the relationship betweenδ^13C and climate factors. We systematically sampled the surface sediments in Otindag dune field,total 42 samples were collected to a depth of approximately 5cm for organic carbon isotope analysis in the field. After pretreatment in laboratory, samples were measured by Thermo Finnigan MAT DELTAp~u~ XP mass spectrometer, with a precision better than 0.4%o. Climate data of meteorological stations was collected and spatial interpolations were accomplished using ArcGIS package,and climate factors（MAT and MAP） of each sampling site were extracted. Combine with obtained vegetation type data in each sampling site, quantitative relationship between soil organic carbon isotope and climate factors can be reconstructed. The results show that δ^13C value of the surface sediments in the Otindag dune field is between -25.0‰ and -19.4%0, with an average of-22.2‰. On the basis of the two-member mixing model,the C4 plants account for 0- 46% biomass with an average of 17.9% in this dune field, which was consistent with modern vegetation investigation study. In addition,the analysis also shows that there is a significant correlation （R2= 0. 5821, n =42, p〈0. 001 ） between the C4 biomass and the annual precipitation,while no clear relationship between the C4 biomass and the annual temperature（R2 =0. 0285） ,indicating that the annual precipitation is a major factor controlling the C4 biomass,while the temperature has little influence on C4 plants. Finally, an empirical equation was established between the 613C value and the annual precipitation in the Otindag dune field（y=-0. 0137x-18. 555 ,R^2 =0. 6015, n=42,p〈0. 001 ）,where y is δ^13C （‰）,and x is MAP（mm）. This equation can be used to reconstruct Holocene precipitation in Otindag dune field.