表土分粒级碳酸盐与碳同位素分布特征及其风尘源区示踪意义  

Distributional Characteristics of Carbonate and Carbon Isotopic Compositions in Different Grain-Size Surface Soils Fractions and Their Implications for Dust Provenance

作　　者：谢远云[1] 孟杰[1] 郭令芬[1] 王艳茹[1] 何葵[1] 

机构地区：[1]黑龙江省普通高等学校地理环境遥感监测重点实验室,哈尔滨师范大学,黑龙江哈尔滨150025

出　　处：《地理与地理信息科学》2012年第6期90-95,共6页Geography and Geo-Information Science

基　　金：国家自然科学基金项目(41072259)

摘　　要：对科尔沁沙地、松嫩沙地及哈尔滨道路松散裸土等不同区域表土样品进行粒度分级,分别测定碳酸盐含量和碳同位素组成,发现大部分沙地样品和全部道路表土样品的碳酸盐含量随粒度变细而增大。松嫩沙地的部分样品和科尔沁沙地的大部分样品碳酸盐含量随粒度变化还表现出其它复杂关系,风成砂和经历过强烈成壤作用改造的沙地样品中的碳酸盐含量与粒度的关系皆表现为随粒度变细而减小;大部分沙地样品和道路表土样品不同粒级组分的碳酸盐δ13 C组成表现出随粒度变细而趋于偏正的特征,但变化范围较小。松嫩沙地和科尔沁沙地碳酸盐含量的地区差异性极不明显,且各粒级组分碳酸盐含量的变化幅度大大超过了其碳酸盐区域差异值,故不能作为区分松嫩沙地和科尔沁沙地风尘源区的示踪指标;而科尔沁沙地和松嫩沙地碳酸盐δ13 C组成存在明显差异,且不同粒级组分碳酸盐δ13 C值差别较小,是一个比碳酸盐含量更好的风尘源区示踪指标。Sandland samples have be collected from Horqin sandland and Dumeng sandland in Songnen Plain,at one time, samples also are collected from city road loose bare soils. Then carbonate volume and carbon isotopic compositions of these samples are measured, respectively. The results show that carbonate volume of most samples raise with decreasing grain size, but rela- tions between carbonate volume and grain size are not only a relation that carbonate volume becomes high with decreasing grain size, but also have other much complex relations. It is believed that the carbonate volume of eolian sand and sandy land samples undergoing transform of violent pedogenesis decreases with decreasing size of sample particles. The varied scopes of carbon isotopic compositions of different grain size fractions of most samples in Dumeng sandland and road loose bare soils and all samples in Horqin sandland are fairly minor, and express the characteristics of increase with decreasing grain size, but the varied changes are very slight. The carbonate volumes arenrt a good dust source region tracer indicator of distinguishing between Dumeng sand- land and Horqin sandland because of not very obvious regional differences of carbonate volumes between Dumeng sandland and Horqin sandland, and of variations of carbonate volumes in different grain size fractions that is much higher than the different value of carbonate volumes between Dumeng sandland and Horqin sandland. However, there exist the obvious differences between carbon isotopic compositions in Dumeng sandland and Horqin sandland, and the differences of δ^13C compositions in different grain size fractions are very slight, indicating that carbonate carbon isotopic compositions in dust fallouts is a better tracing index indicating eolian dust provenance than carbonate contents.

关 键 词：碳酸盐 碳酸盐碳同位素 分粒级组分 风尘源区示踪 

分 类 号：P531[天文地球—古生物学与地层学]