The coal seams in the Permian Taiyuan Formation and the Carboniferous Shanxi Formation are the primary reservoirs for the coalbed methane （CBM） in the Hancheng region in the Ordos Basin. In this paper, the origin an...The coal seams in the Permian Taiyuan Formation and the Carboniferous Shanxi Formation are the primary reservoirs for the coalbed methane （CBM） in the Hancheng region in the Ordos Basin. In this paper, the origin and evolution of waters associated with CBM production were studied on the basis of water chemistry and isotopes including the chloride and iodine compositions, oxygen and hydrogen stable isotopes, and radioactive isotope ratio of ^129I/^127I. The ratio of ^129I/^127I of water was determined by accelerator mass spectrometry （AMS）. The result shows that the formation water is of NaHCO3 and NaCl types with the total dissolved solids （TDS） varying from 1532.29 mg/L to 7061.12 mg/L. The values of ^129I and I/CI ratio indicate that the formation waters were diluted by meteoric water. The ^129I/^127I ratios range from 6.6×10^-13 to 1459.5~10-13. The ^129I/^127I ratios for most of the samples are between the ^129I/^127I initial value and that of recent anthropogenic water. This age of the formation water samples, obtained through the ^129I decay curve method, ranges from 0 Ma to 18.5 Ma, suggesting that the waters from the Taiyuan Formation and the Shanxi Formation are very young. Two different origins of water are identified in the Hancheng region. One group is dominated by pre-anthropogenic meteoric water, and is characterized by ^129I/^127I ratios lower than the initial value of 15×10^-13 and δD, δ^18O values of waters below the Global Meteoric Water Line. The other group is characterized by ^129I/^127I ratios in excess of 15×10^-13, which has undergone variable degrees of dilution by recent anthropogenic water.展开更多
In the present study, the analytical method for ^129iodine （^129I） in ferromanganese crusts is developed and ^129iodine/^127iodine （^129I/^127I） ratio in ferromanganese crusts is measured by the accelerator mass s...In the present study, the analytical method for ^129iodine （^129I） in ferromanganese crusts is developed and ^129iodine/^127iodine （^129I/^127I） ratio in ferromanganese crusts is measured by the accelerator mass spectrometry （AMS）. The developed method is applied to analyze ^129I/^127I ratio in two ferromanganese crusts MP5D44 and CXD08-1 collected from the Mid-Pacific Ocean. The results show that ^129I/^127I ratio in MP5D44 and CXD08-1 crusts varies from 7×10^-14 to 1.27×10^-12, with the lowest value falling on the detection limit level of AMS reported by previous literatures. For the depth distribution of ^129I/^127I, it is found that both MP5D44 and CXD08-1 crusts have two growth generations, and the ^129I/^127I profiles in two generations all displayed an approximate exponential decay. According to the ^129I/^127I ratio, the generate age of bottom layer of MP5D44 and CXD08-1 was estimated to be 54.77 and 69.69 Ma, respectively.展开更多
The English Channel(the Channel)represents a major sink and transport pathway of anthropogenic radioactive ^(129)I.Despite this important role,data concerning the distribution of ^(129)I in seawater of the Channel are...The English Channel(the Channel)represents a major sink and transport pathway of anthropogenic radioactive ^(129)I.Despite this important role,data concerning the distribution of ^(129)I in seawater of the Channel are scarce,and most of existing data are restricted to the eastern part of the Channel.The advection and dispersion of ^(129)I from the French coast toward the central and further the English coast,especially in the Channel west of Cap de La Hague,are not fully investigated.We present results of iodine isotopes( ^(127)I and ^(129)I)analyses of surface water samples collected along the central English Channel in October,2010.The data show high ^(129)I concentrations between Dover Strait and La Hague,followed by a dramatic drop towards the Celtic Sea and reveal the dispersal of ^(129)I towards central and northern part of the Channel.Our observation also implies that the entire British coast is contaminated by ^(129)I. ^(129)I levels in the westernmost English Channel,close to the English coast,may reflect combined influences from La Hague and Sellafield.Evolution of ^(129)I between 2005 and 2010 suggests a strong link to temporal marine discharges from La Hague plant.The discharges from the nuclear reprocessing facility have continued since 2010 and thus an ecological evaluation of ^(129)I radioactive hazards in the environment of the Channel may be needed.展开更多
基金supported by National Basic Research Program of China(Grant No.2009CB219601)
文摘The coal seams in the Permian Taiyuan Formation and the Carboniferous Shanxi Formation are the primary reservoirs for the coalbed methane （CBM） in the Hancheng region in the Ordos Basin. In this paper, the origin and evolution of waters associated with CBM production were studied on the basis of water chemistry and isotopes including the chloride and iodine compositions, oxygen and hydrogen stable isotopes, and radioactive isotope ratio of ^129I/^127I. The ratio of ^129I/^127I of water was determined by accelerator mass spectrometry （AMS）. The result shows that the formation water is of NaHCO3 and NaCl types with the total dissolved solids （TDS） varying from 1532.29 mg/L to 7061.12 mg/L. The values of ^129I and I/CI ratio indicate that the formation waters were diluted by meteoric water. The ^129I/^127I ratios range from 6.6×10^-13 to 1459.5~10-13. The ^129I/^127I ratios for most of the samples are between the ^129I/^127I initial value and that of recent anthropogenic water. This age of the formation water samples, obtained through the ^129I decay curve method, ranges from 0 Ma to 18.5 Ma, suggesting that the waters from the Taiyuan Formation and the Shanxi Formation are very young. Two different origins of water are identified in the Hancheng region. One group is dominated by pre-anthropogenic meteoric water, and is characterized by ^129I/^127I ratios lower than the initial value of 15×10^-13 and δD, δ^18O values of waters below the Global Meteoric Water Line. The other group is characterized by ^129I/^127I ratios in excess of 15×10^-13, which has undergone variable degrees of dilution by recent anthropogenic water.
基金The National Natural Science Foundation of China under contract No.41073044
文摘In the present study, the analytical method for ^129iodine （^129I） in ferromanganese crusts is developed and ^129iodine/^127iodine （^129I/^127I） ratio in ferromanganese crusts is measured by the accelerator mass spectrometry （AMS）. The developed method is applied to analyze ^129I/^127I ratio in two ferromanganese crusts MP5D44 and CXD08-1 collected from the Mid-Pacific Ocean. The results show that ^129I/^127I ratio in MP5D44 and CXD08-1 crusts varies from 7×10^-14 to 1.27×10^-12, with the lowest value falling on the detection limit level of AMS reported by previous literatures. For the depth distribution of ^129I/^127I, it is found that both MP5D44 and CXD08-1 crusts have two growth generations, and the ^129I/^127I profiles in two generations all displayed an approximate exponential decay. According to the ^129I/^127I ratio, the generate age of bottom layer of MP5D44 and CXD08-1 was estimated to be 54.77 and 69.69 Ma, respectively.
基金The National Natural Science Foundation of China under contract No.41603122the Everest Scientific Research Program of Chengdu University of Technology under contract Nos 2020ZF11405 and 2021ZF11419+3 种基金the Open Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection under contract No.SKLGP2019K013the Open Fund of Sichuan Vanadium&Titanium Industry Development Research Center under contract No.2020VTCY-Z-01the Fund of Science and Technology Department of Sichuan Province under contract No.2021JDTD0013the Foundation for Young Backbone Teachers of Chengdu University of Technology,2022。
文摘The English Channel(the Channel)represents a major sink and transport pathway of anthropogenic radioactive ^(129)I.Despite this important role,data concerning the distribution of ^(129)I in seawater of the Channel are scarce,and most of existing data are restricted to the eastern part of the Channel.The advection and dispersion of ^(129)I from the French coast toward the central and further the English coast,especially in the Channel west of Cap de La Hague,are not fully investigated.We present results of iodine isotopes( ^(127)I and ^(129)I)analyses of surface water samples collected along the central English Channel in October,2010.The data show high ^(129)I concentrations between Dover Strait and La Hague,followed by a dramatic drop towards the Celtic Sea and reveal the dispersal of ^(129)I towards central and northern part of the Channel.Our observation also implies that the entire British coast is contaminated by ^(129)I. ^(129)I levels in the westernmost English Channel,close to the English coast,may reflect combined influences from La Hague and Sellafield.Evolution of ^(129)I between 2005 and 2010 suggests a strong link to temporal marine discharges from La Hague plant.The discharges from the nuclear reprocessing facility have continued since 2010 and thus an ecological evaluation of ^(129)I radioactive hazards in the environment of the Channel may be needed.
