The chemical fractions,i.e.,water soluble(WS),exchangeable(Ex),carbonate(Car),weakly organic(WO),Fe-Mn oxide(FMO),strongly organic(SO),residual(Res) fraction,of Pb in irrigated soils in South China were investigated b...The chemical fractions,i.e.,water soluble(WS),exchangeable(Ex),carbonate(Car),weakly organic(WO),Fe-Mn oxide(FMO),strongly organic(SO),residual(Res) fraction,of Pb in irrigated soils in South China were investigated by a modified Tessier sequential extraction technique.The results show that the chemical fraction of Pb in soil is mainly the Res fraction and followed by FMO fraction,and the WS,WO,FMO,and SO fractions in topsoils(0-10 cm) are higher than those in subsoils(30-40 cm).The sum of contents of WS and Ex fractions(SWE) in topsoils is significantly positively related with that in subsoils,indicating the strong mobility of Pb in WS and Ex fractions in soils,and the SWE in soils is higher than the German trigger value for the transfer path soil-plant,indicating the high bioavailability of Pb in soils of this area.Fortunately,SWE and the ratio of WS and Ex fractions(RWE) to the sum of all fractions generally decrease with the soil depth in soil profile and the RWE in soil profile is lower than 0.5%,indicating the low pollution risk for Pb in groundwater.In addition,soil particles,pH and Fe2O3 play an important role in the impact of mobility and chemical fractions of Pb in soils.展开更多
Based on a synthetic geological study of drilling, well logging and core observations, two main genetic types of Chang 9sand body in Odors Basin were recognized, which included two effects, that is, delta environment ...Based on a synthetic geological study of drilling, well logging and core observations, two main genetic types of Chang 9sand body in Odors Basin were recognized, which included two effects, that is, delta environment and tractive current effects that lead to the development of mouth bar, distal bar, sheet sand and other sand bodies of subaerial and subaqueous distributary channel,natural levee, flood fan and delta front, and shore-shallow lake environment and lake flow transformation effects that result in the development of sandy beach bar, sheet sand and other sand bodies. Chang 9 sand body mainly developed five basic vertical structures, namely box shape, campaniform, infundibuliform, finger and dentoid. The vertical stacking patterns of multilayer sand body was complex, and the common shapes included box shape + box shape, campaniform + campaniform, campaniform + box shape, infundibuliform + infundibuliform, campaniform + infundibuliform, box shape + campaniform, box shape + infundibuliform,and finger + finger. Based on the analysis on major dominating factors of vertical structure of sand body, sedimentary environment,sedimentary facies and rise, fall and cycle of base level are identified as the major geological factors that control the vertical structure of single sand body as well as vertical stacking patterns and distribution of multistory sand bodies.展开更多
基金Project(41103059) supported by the National Natural Science Foundation of ChinaProject(2010CB428806-2) supported by the National Basic Research Program of China
文摘The chemical fractions,i.e.,water soluble(WS),exchangeable(Ex),carbonate(Car),weakly organic(WO),Fe-Mn oxide(FMO),strongly organic(SO),residual(Res) fraction,of Pb in irrigated soils in South China were investigated by a modified Tessier sequential extraction technique.The results show that the chemical fraction of Pb in soil is mainly the Res fraction and followed by FMO fraction,and the WS,WO,FMO,and SO fractions in topsoils(0-10 cm) are higher than those in subsoils(30-40 cm).The sum of contents of WS and Ex fractions(SWE) in topsoils is significantly positively related with that in subsoils,indicating the strong mobility of Pb in WS and Ex fractions in soils,and the SWE in soils is higher than the German trigger value for the transfer path soil-plant,indicating the high bioavailability of Pb in soils of this area.Fortunately,SWE and the ratio of WS and Ex fractions(RWE) to the sum of all fractions generally decrease with the soil depth in soil profile and the RWE in soil profile is lower than 0.5%,indicating the low pollution risk for Pb in groundwater.In addition,soil particles,pH and Fe2O3 play an important role in the impact of mobility and chemical fractions of Pb in soils.
基金Project(2011D-5006-0105)supported by the Technology Innovation Foundation of CNPC,ChinaProject(SZD0414)supported by the Key Discipline of Mineral Prospecting and Exploration of Sichuan Province,China
文摘Based on a synthetic geological study of drilling, well logging and core observations, two main genetic types of Chang 9sand body in Odors Basin were recognized, which included two effects, that is, delta environment and tractive current effects that lead to the development of mouth bar, distal bar, sheet sand and other sand bodies of subaerial and subaqueous distributary channel,natural levee, flood fan and delta front, and shore-shallow lake environment and lake flow transformation effects that result in the development of sandy beach bar, sheet sand and other sand bodies. Chang 9 sand body mainly developed five basic vertical structures, namely box shape, campaniform, infundibuliform, finger and dentoid. The vertical stacking patterns of multilayer sand body was complex, and the common shapes included box shape + box shape, campaniform + campaniform, campaniform + box shape, infundibuliform + infundibuliform, campaniform + infundibuliform, box shape + campaniform, box shape + infundibuliform,and finger + finger. Based on the analysis on major dominating factors of vertical structure of sand body, sedimentary environment,sedimentary facies and rise, fall and cycle of base level are identified as the major geological factors that control the vertical structure of single sand body as well as vertical stacking patterns and distribution of multistory sand bodies.
