| 引用本文: | 孔凡翠,杨英魁,马玉军,沙占江,凌智永,王建萍.大柴旦盐湖中镭同位素分布特征来源及示踪意义.湖泊科学,2021,33(2):632-646. DOI:10.18307/2021.0227 |
| Kong Fancui,Yang Yingkui,Ma Yujun,Sha Zhanjiang,Ling Zhiyong,Wang Jianping.The distribution and sources of radium isotopes in Da Qaidam salt lake. J. Lake Sci.2021,33(2):632-646. DOI:10.18307/2021.0227 |
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| 大柴旦盐湖中镭同位素分布特征来源及示踪意义 |
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孔凡翠1,2, 杨英魁3, 马玉军4, 沙占江4,5, 凌智永1,2, 王建萍1,2
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1.中国科学院青海盐湖研究所, 中国科学院盐湖资源综合高效利用重点实验室, 西宁 810008;2.青海省盐湖地质与环境重点实验室, 西宁 810008;3.青海大学, 西宁 810016;4.青海师范大学地理科学学院, 青海省自然地理与环境过程重点实验室, 青藏高原地表过程与生态保育教育部重点实验室, 西宁 810008;5.高原科学与可持续发展研究院, 西宁 810016
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| 摘要: |
| 为了查明大柴旦湖周围水体相互作用过程，2016年3月和7月分别采集了大柴旦周围多种水体样品、悬浮颗粒物和湖底沉积物.测试了大柴旦盐湖、深部地下热水、表层地下水热水、浅层地下水、河流水体中镭同位素的活度值，通过解吸和扩散实验，获得了河流悬浮颗粒物和湖底沉积物扩散的镭同位素活度值.结果表明：河口区（3L10、3L11、3L12）223Ra、224Ra、226Ra和228Ra活度比湖中心的活度值高，湖水中223Ra、224Ra、226Ra和228Ra活度先随着盐度的增加而升高，当盐度大于168.99‰时，则随着盐度的增加而降低，这表明镭同位素在进入湖体是先发生解吸，后发生镭同位素的共沉淀.深部地下热水223Ra、224Ra和228Ra的活度值是表层地下热水223Ra、224Ra和228Ra活度值的3~4倍，而226Ra活度值正好相反，表层地下热水中226Ra的活度值比深部地下热水中226Ra的活度值高，在表层具有明显的积累现象.这是由于短半衰期223Ra、224Ra和228Ra发生衰减，而长半衰期226Ra得到积累的原因，从而表明镭同位素的运移方向是从深部往上涌的过程.大柴旦盐湖中的镭同位素主要来源于深部地下热水、浅层地下水和河流.大柴旦周围水循环过程是雨和冰雪融水下渗补给深部和浅层地下水以及地表径流；深部地下热水一部分上涌至表层，经过出山口之后全部转化为浅层地下水，一部分通过深大断裂汇集到大柴旦湖；浅层地下水直接汇集到湖盆；地表径流在山区下渗补给浅层地下水，丰水期汇入到湖盆. |
| 关键词: 镭同位素 镭同位素来源 水循环 大柴旦盐湖 |
| DOI：10.18307/2021.0227 |
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| 基金项目:中国科学院青年创新促进会项目（2018468）、国家自然科学基金项目（41702268）、青海科技厅项目（2020-ZJ-974Q，2021-ZJ-755）、中国科学院重点部署项目（ZDRW-ZS-2020-3）和第二次青藏高原综合科学考察项目（2019QZKK0805）联合资助. |
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| The distribution and sources of radium isotopes in Da Qaidam salt lake |
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Kong Fancui1,2, Yang Yingkui3, Ma Yujun4, Sha Zhanjiang4,5, Ling Zhiyong1,2, Wang Jianping1,2
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1.Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, P. R. China;2.Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Xining 810008, P. R. China;3.Qinghai University, Xining 810016, P. R. China;4.College of Geographical Sciences, Qinghai Normal University, Key Laboratory of Natural Geography and Environmental Process in Qinghai Province Education, Qinghai Normal University, Key Laboratory of Tibetan Plateau Land Surface Processes and Ecological Conservation, Ministry of Education, Xining 810008, P. R. China;5.Academy of Plateau Science and Sustainability, Xining 810016, P. R. China
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| Abstract: |
| In order to understand hydrologic cycle around Da Qaidam salt lake, water and suspended particulate matter (SPM) and sediments samples were collected in March and July in 2016. The activities of radium isotopes of brine water, deep hot spring water, shallow spring water and river water were measurement. Moreover, the radium isotopes activities from SPM and sediment were obtained by experiments of desorption and diffusion. The results showed that the activities of 223Ra, 224Ra, 226Ra and 228Ra of lake water in estuary were higher than those of in lake centre, and they increase with the salinity, and then decrease with the salinity when salinity is greater than 168.99‰, suggesting that radium were desorbed when groundwater or river water met salt lake water at beginning at low salinity, and radium were co-precipitation with Ca or Ba at high salinity. The activity value of 223Ra, 224Ra and 228Ra in deep hot spring water are about 3-4 times as much as those in shallow hot spring water. However, 226Ra activity values in shallow hot spring water are higher than that of deep hot spring water,which show an obvious accumulation phenomenon at the surface. This is because half-life of 223Ra, 224Ra and 228Ra is very short, it is easy to attenuate, while the long half-life 226Ra easy to accumulate, indicating that the migration direction of Radium is from deep to upwelling. The sources of radium in Da Qaidam salt lake are mainly from deep hot spring water, shallow groundwater and river water. The infiltration of rain and melt snow water to recharge deep and shallow groundwater and surface runoff. A part of the deep hot water rises to the surface, and then converted into shallow groundwater after passing through the mountain pass. The other part of deep hot water were flowed into Da Qaidam salt lake by the deep fault. The shallow groundwater entering into the lake basin. Surface runoff supply shallow groundwater by infiltration at and inflow into the lake basin during wet season. |
| Key words: Radium isotopes the source of radium hydrologic cycle Da Qaidam salt lake |
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