洞穴新生碳酸钙碳同位素对地表石漠化的指示意义  

Significance of δ^(13)C of New Calcium Carbonate from Caves to Surface Rocky Desertification

作　　者：刘子琦[1] 熊康宁[2] 盈斌[2] 

机构地区：[1]西南大学地理科学学院,重庆400715 [2]贵州师范大学中国南方喀斯特研究院,贵州贵阳550001

出　　处：《安徽农业科学》2011年第5期2896-2899,2922,共5页Journal of Anhui Agricultural Sciences

基　　金：西南大学博士研究基金(SWUB2008060);国家自然科学基金(41001367);"十一五"国家科技攻关(支撑)计划基金(2006BAC01A09);贵州省科技计划课题(黔科合S字[2007]1061号)

摘　　要：[目的]研究洞穴新生碳酸钙碳同位素对地表石漠化的指示意义。[方法]采用质谱仪分别测定了贵州中西部洞穴沉积物中δ18O、δ13C值及植被、土壤样品中δ13C值。[结果]洞穴沉积物δ13C值与地表植被覆盖率有关;冰期的δ13C较重,说明降雨量的减少会导致植被的减少;间冰期时段,较老δ13C之间相似,但与新生碳酸钙的δ13C差异较大,说明现代的人类活动对植被的影响比自然因素变化的影响更明显;洞穴沉积物δ13C值基本反映了地表植被、土壤中有机碳δ13C值的变化,植物覆盖率和植被类型是影响洞穴沉积物δ13C值重要因素,地表石漠化的等级越高,洞穴沉积物中δ13C值越重。[结论]洞穴沉积物δ13C记录为研究石漠化演变奠定了理论基础。[Objective] The aim was to study the guiding significance of δ13C of new calcium carbonate from caves to surface rocky desertification.[Method] The mass spectrometer was adopted to detect the δ18O and δ13C values in the cave sediments and δ13C value in the vegetation and soil samples from Central and Western Guizhou Province.[Result] δ13C value of the cave sediments related to the surface vegetation coverage;the great δ13C value in the glacial period indicated that the decrease of precipitation led to the loss of vegetation;during the interglacial period,δ13C values of the old calcium carbonate were similar but differed largely from that of the new calcium carbonate,which illustrated that nowadays human activity exerted larger impact on vegetation than the changes of natural factors did;the δ13C value of the cave sediment basically reflected the changes of the organic δ13C value in the surface vegetation and soils,vegetation coverage and vegetation type were two important factors influencing the δ13C value of cave sediments,the higher the rocky desertification degree,the larger the δ13C value of the cave sediment.[Conclusion] The record of δ13C value of the cave sediment provided theoretical foundation for the evolution of rocky desertification.

关 键 词：新生碳酸钙 碳氧同位素 石漠化 贵州 

分 类 号：X171.4[环境科学与工程—环境科学]