干旱区生态环境知识资源中心(Arid): 中国西北干旱区不同粒径表土碳酸盐含量及碳、氧同位素组成

Arid

	中国西北干旱区不同粒径表土碳酸盐含量及碳、氧同位素组成
其他题名	Carbonate content and oxygen and carbon isotope composition of different grain size samples from the surface soil of arid land in northwest China
	王宁; 刘卫国
来源期刊	干旱区地理
ISSN	1000-6060
出版年	2010
卷号	33 期号:2 页码:158-163
中文摘要	通过对我国典型干旱区表土分粒级样品的碳酸盐含量及其碳氧同位素的测试,结果显示:我国西北干旱区表土不同粒级样品的碳酸盐含量以及碳氧稳定同位素组成存在较大的差异.随着粒径的减小,碳酸盐含量逐渐升高,氧同位素逐渐偏正,碳同位素逐渐偏负.可以认为细颗粒组分中土壤次生碳酸盐相对比例大,而粗颗粒组分中原生碳酸盐相对占优势.而次生碳酸盐氧同位素可能受蒸发的控制,碳同位素更多的受植被的影响,所以表现出细颗粒组分较粗颗粒组分碳酸盐的氧同位素更偏正,而碳同位素更偏负.因此,干旱区表土细颗粒组分碳酸盐能更好地反映成壤过程中次生碳酸盐形成时期的气候环境信息.
英文摘要	The widely distributed arid land in northwest China provides a perfect object for investigating the envi-ronment change.The surface soil in arid land is an important carrier of the modem environment change process in-formation.In order to further understand the factors affecting the carbon and oxygen isotope composition of surface soil in arid land,this paper studied the surface soil samples in Xinjiang and Gansu Province,a typical arid land in northwest China.These samples were separated into several different grain sizes fractions by sedimentation,floata-tion and filtration.Their carbonate contents were measured with titration method and their oxygen and carbon iso-tope composition was online analyzed using MAT-252.The results of the study indicate that there is a good corre-lation between the carbonate content and the grain size.The carbonate content increases with the grain size decrea-sing.The results of isotope analysis show that the stable oxygen and carbon isotopes of different grain size samples are distinctly different.As the grain size decreasing,the oxygen isotope increases and the carbon isotope gets more negative.According to the above results,the conclusion can be drawn that the pedogenie carbonate is regnant in fine grain samples;while the primary carbonate predominates in the coarse grain group.The oxygen isotope of ped-ogenie carbonate may be controHed by the evaporation.The oxygen isotope of pedogenic carbonate mainly depends on the oxygen isotope composition of soil water.Strong evaporation brings isotopic fraetionation,and then leads to the enrichment of ~(18)O in soil water.However the carbon isotope of pedogenie carbonate may be affected by vegeta-tion.The soil carbon dioxide is an important contributor of the carbon isotope of pedogenie carbonates.Moreover the soil respiration releases isotopieally light carbon dioxide,and then leads to the carbon isotope of soil carbon di-oxide more negative.Therefore,the oxygen isotope shows more positive and carbon isotope more negative in pedo-genic carbonate than in primary carbonate.Compared with the coarse grain groups,the oxygen isotope of fine grain group is more positive and the carbon isotope is more negative.The surface soil in the arid land,the carbonate in fine grain group can be regarded as pedogenic carbonate.It may better reflect the information of the climate and en-vironment conditions during the process of the formation of the pedogenic carbonate.Above results are very useful for the research on climate and environment of the past in the arid land.
中文关键词	表土 ; 粒径 ; 碳酸盐含量 ; 碳氧同位素 ; 中国
英文关键词	surface soil grain size carbonate content carbon and oxygen isotope China
语种	中文
国家	中国
收录类别	CSCD
WOS类目	GEOLOGY
WOS研究方向	Geology
CSCD记录号	CSCD:3867336
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/224986
作者单位	中国科学院地球环境研究所, 黄土与第四纪地质国家重点实验室, 西安, 陕西 710075, 中国
推荐引用方式 GB/T 7714	王宁,刘卫国. 中国西北干旱区不同粒径表土碳酸盐含量及碳、氧同位素组成[J],2010,33(2):158-163.
APA	王宁,&刘卫国.(2010).中国西北干旱区不同粒径表土碳酸盐含量及碳、氧同位素组成.干旱区地理,33(2),158-163.
MLA	王宁,et al."中国西北干旱区不同粒径表土碳酸盐含量及碳、氧同位素组成".干旱区地理 33.2(2010):158-163.