贵州草海赵家院子晚更新世泥炭层地球化学特征及其环境意义  

Geochemical Characteristics and Sedimentary Environment of the Epipleistocene Peat on Zhaojiayuanzi Sediment Column in Caohai Basin, Guizhou Province

作　　者：孔凡翠[1,2,3,4] 杨瑞东[3] 沙占江[1] 

机构地区：[1]中国科学院青海盐湖研究所,西宁810008 [2]中国科学院大学,北京100049 [3]贵州大学资源与环境工程学院,贵阳550003 [4]邹城市国土资源局,山东邹城273500

出　　处：《地质论评》2013年第4期716-730,共15页Geological Review

基　　金：国家科技支撑计划项目课题(编号2011BAC02B02);教育部"211"重点学科建设基金项目(编号KST200903)

摘　　要：根据威宁草海赵家院子沉积柱主量元素和微量元素特征以及14C测年分析,探讨了草海地区泥炭沉积速率,晚更新世—全新世古气候演变和沉积物物源环境。元素地球化学测试结果表明,Li、Sc、V、Cr、Ni、Ga、Rb、Sr、Sn、Cs、Ba、Zr、Th、U等14种微量元素在沉积柱上含量变化整体呈现一致性。14C测年显示,赵家院子剖面沉积柱下部泥炭层的年龄大约为33.74±1.79—23.29±0.10kaBP之间,各层的沉积速率自下而上分别是:下部泥炭层148.4mm/ka,上部黑色古土壤层24.3mm/ka,顶部堆积层22.4mm/ka,沉积柱沉积速率由下而上逐渐降低。元素对比值以及多元素之和比值Sr/Ba、Rb/Sr、(CaO+K2O+Na2O)/Al2O3、(Fe2O3+Al2O3)/(MgO+CaO)和CaO/MgO等气候指标显示,从42.37±1.27kaBP到15.6±0.1kaBP时间段内,研究区古气候经历了由温暖较湿润→温暖湿润→温凉干燥→温暖较湿润→温凉湿润的演化。沉积物物源经历了较强烈的化学风化,下部泥炭层风化程度小于上部沉积物的风化程度。Based on the analytical results of major elements, trace elements and 14C age of the Zhaojiayuanzi sediment column in the Caohai Basin, Weining country, Guizhou Province, China, writers discussed the depositional rate of peat, climatic evolution and provenance from Late Pleistocene to Holocene and the source environment of sediment. The results show that trace elements Li, Sc, V, Cr, Ni, Ga, Rb, Sr, Sn, Cs, Ba, Zr, Th, U et al. are consistent throughout the whole column. 14C dating suggests that the age of the basal peat layer in the sediment column is spanned between 33.74 and 23.29 ka BP, and the deposition rates of different layers respectively are 148.4 mm/ka for the bottom peat layer, 24.3 mm/ka for the black paleosol, 22.4 mm/ka for top layer, so that the deposition rates gradually reduce from the bottom to top.The climate indicators, such as some element ratios （Sr/Ba, Sr/Cu, Rb/Sr, MgO/CaO）, and the multi-elements ratios [（CaO ＋ K2O ＋ Na2O）/Al2O3, （Fe2O3 ＋ Al2O3）/（MgO ＋ CaO）] suggest that, during the period from 42.37 ± 1.27 ka BP to 15.60 ± 0.10 ka BP, the ancient climate at ZhaojiaYuanzi area evolved from warm—slight humidwarm—wetwarm—drycool—some moistcool—moist.The source of sediments has experienced an intense chemical weathering, in which the bottom peat layer, however, was less weathered.

关 键 词：泥炭 元素地球化学 沉积速率 草海 贵州 

分 类 号：P534.631[天文地球—第四纪地质学]