Behavior of REE Fractionation during Weathering of Dolomite Regolith Profile in Southwest China  

作　　者：GONG Qingjie ZHANG Gaixia ZHANG Jing JIANG Biao MA Nan 

机构地区：[1]State Key Laboratory of Geological Processes andMineral Resources, China University of Geosciences, Beijing 100083, China [2]Faculty of Earth Sciences and Resources, China University of Geosciences, No.29 Xueyuan Road, Haidian District, Beijing 100083, China

出　　处：《Acta Geologica Sinica(English Edition)》2010年第6期1439-1447,共9页地质学报（英文版）

基　　金：supported by the National Basic Research Program of China(973 Program) (2009CB421006);the State Key Laboratory of Geological Processes and Mineral Resources (GPMR200843)

摘　　要：REE fractionation during the weathering of dolomite has been recognized for decades.A regolith profile on dolomite in southwest Yunnan of China was selected to investigate the behaviors of REE during weathering.The weathering of dolomite is divided into two stages：the pedogenesis stage and soil evolution stage,corresponding to the saprolites and soils respectively in the regolith profile. SiO_2,TiO_2,P_2O_5,Zr,Hf,Nb and Ta were immobile components during the weathering by and large, while Al_2O_3,K_2O and Fe_2O_3 were lost during the soil evolution stage in the physical form（clay minerals probably）.REE were fractionated during the whole weathering of dolomite.The field weathering profile and the lab acid-leaching experiments on dolomite indicate that MREE were enriched clearly relative to other REE during the pedogenesis stage in a ＂capillary ascending-adsorption＂ mechanism, but they did not fractionate clearly in the soil evolution stage.REE were lost and accumulated in the weathering front of dolomite during the soil evolution stage in a ＂physical-chemical leaching＂ mechanism.REE fractionation during the weathering of dolomite has been recognized for decades.A regolith profile on dolomite in southwest Yunnan of China was selected to investigate the behaviors of REE during weathering.The weathering of dolomite is divided into two stages：the pedogenesis stage and soil evolution stage,corresponding to the saprolites and soils respectively in the regolith profile. SiO_2,TiO_2,P_2O_5,Zr,Hf,Nb and Ta were immobile components during the weathering by and large, while Al_2O_3,K_2O and Fe_2O_3 were lost during the soil evolution stage in the physical form（clay minerals probably）.REE were fractionated during the whole weathering of dolomite.The field weathering profile and the lab acid-leaching experiments on dolomite indicate that MREE were enriched clearly relative to other REE during the pedogenesis stage in a ＂capillary ascending-adsorption＂ mechanism, but they did not fractionate clearly in the soil evolution stage.REE were lost and accumulated in the weathering front of dolomite during the soil evolution stage in a ＂physical-chemical leaching＂ mechanism.

关 键 词：REE FRACTIONATION WEATHERING DOLOMITE 

分 类 号：P588.245[天文地球—岩石学] O614.33[天文地球—地质学]