柴达木盆地大盐滩矿区深层晶间卤水的成因
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摘要
柴达木盆地西部昆特依盐湖大盐滩矿区地下卤水资源丰富,具有很好的开发利用前景。野外采取了大盐滩矿区不同深度(9.8～133 m)晶间卤水样品和冷湖构造油田水样品,分析了卤水的水化学组成和氢氧同位素值。结果显示,晶间卤水矿化度较高(平均为363.94 g/L)且富K~+,水化学类型为硫酸镁亚型;油田水矿化度较低(平均为39.02 g/L),富Ca~(2+)和Sr~(2+),水化学类型为氯化物型。离子含量及钠氯系数和溴氯系数分析显示,大盐滩矿区晶间卤水主要为大气降水汇聚后经蒸发作用形成,深层晶间卤水(30～133 m)具有大气降水盐岩溶滤成因及受具有深部来源性质油田水补给的特征。氢氧同位素组成分析表明,卤水均发生了明显的"氧同位素正漂移"现象,推断深层晶间卤水较高的δ~(18)O、δD值与浅层晶间卤水(9.8～11.5 m)以及大气降水溶滤盐岩沿断裂下渗补给有关。
Dayantan Mine Area,which is located in the west of Kunty playa in Qaidam basin,has rich underground brine resources and has a prospect of exploitation and utilization.10 oilfield brine samples in Dayantan playa were taken and 10 samples of intercrystalline brine were taken from different depths(9.8～133 m) of the Dayantan Mine Area in this study.The chemical compositions,hydrogen and oxygen isotopic characteristics of brine were analyzed.The results show that the salinity of intercrystalline brines is high(with an average of 363.94 g/L),and these brines have a high content of K~+ and are enriched in Mg~(2+), SO■.The chemical type of intercrystalline brines is magnesium sulfate subtype.According to the ion contents and water chemistry characteristic coefficient(rNa/rCl and rBr×10~3/rCl),the result shows the intercrystalline brines are mainly formed by atmospheric precipitation which has been converged and evaporated,and the deep intercrystalline brines(30-133 m)are derived from atmospheric precipitation dissolving rock salt and supplied by oilfield brines which have properties of deep origins.The hydrogen and oxygen isotopic compositions show that there is an obvious phenomenon of "oxygen isotopic positive deviation" in deep brine,which can be inferred that it is related to the infiltration supply of the shallow brines(9.8-11.5 m)and the atmospheric precipitation dissolved rock salt along the fractures.
Dayantan Mine Area,which is located in the west of Kunty playa in Qaidam basin,has rich underground brine resources and has a prospect of exploitation and utilization.10 oilfield brine samples in Dayantan playa were taken and 10 samples of intercrystalline brine were taken from different depths(9.8～133 m) of the Dayantan Mine Area in this study.The chemical compositions,hydrogen and oxygen isotopic characteristics of brine were analyzed.The results show that the salinity of intercrystalline brines is high(with an average of 363.94 g/L),and these brines have a high content of K~+ and are enriched in Mg~(2+), SO■.The chemical type of intercrystalline brines is magnesium sulfate subtype.According to the ion contents and water chemistry characteristic coefficient(rNa/rCl and rBr×10~3/rCl),the result shows the intercrystalline brines are mainly formed by atmospheric precipitation which has been converged and evaporated,and the deep intercrystalline brines(30-133 m)are derived from atmospheric precipitation dissolving rock salt and supplied by oilfield brines which have properties of deep origins.The hydrogen and oxygen isotopic compositions show that there is an obvious phenomenon of "oxygen isotopic positive deviation" in deep brine,which can be inferred that it is related to the infiltration supply of the shallow brines(9.8-11.5 m)and the atmospheric precipitation dissolved rock salt along the fractures.
引文
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[4] 李建森,李廷伟,马海州,等.柴达木盆地西部新近系和古近系油田卤水水化学特征及其地质意义[J].水文地质工程地质,2013,40(6):28-36.
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[6] 樊启顺,马海州,谭红兵,等.柴达木盆地西部卤水特征及成因探讨[J].地球化学,2007,36(6):601-611.
[7] 樊启顺,马海州,谭红兵,等.柴达木盆地西部卤水水化学特征与找钾研究[J].地球学报,2007,28(5):446-455.
[8] 中国科学院青海盐湖研究所.卤水和盐的分析方法[M].北京:科学出版社,1988:29-237.
[9] 瓦良亚什科M T.钾盐矿床形成的地球化学规律[M].范立,译.北京:中国工业出版社,1965:30-57.
[10] White D E,Hem J D,Waring G A.Data of geochemistry—chemical composition of surface waters[M].Washington:United States Go-vernment Printing Office,1963:1-67.
[11] Kharaka Y K,Law D M,et al.Role of organic species dissolved in formation water from sedimentary basins inmineral diagenesis[J].Role of organic Matt er in Sediment Diagenests,1986,38:111-122.
[12] 林晓英,曾溅辉,杨海军,等.塔里木盆地哈得逊油田石炭系地层水化学特征及成因[J].现代地质,2012,26(2):377-383.
[13] 汪蕴璞.深层卤水形成问题及研究方法[M].北京:地质出版社,1982:68-69.
[14] 汪蕴璞.深层卤水形成问题及其研究方法[M].北京:地质出版社,1982:67-74.
[15] Craig H.Isotopic variations in meteoric waters [J].Science,1961,133(3465):1702-1703.
[2] 青海省地质矿产开发院.大盐滩钾矿详查报告(内部资料)[R]西宁:青海省地质矿产开发院,2006.
[3] 李宝兰,高东林,袁小龙,等.昆特依大盐滩矿床晶间卤水的赋存特征研究[J].盐湖研究,2014,22(2):26-32.
[4] 李建森,李廷伟,马海州,等.柴达木盆地西部新近系和古近系油田卤水水化学特征及其地质意义[J].水文地质工程地质,2013,40(6):28-36.
[5] 李廷伟,谭红兵,樊启顺.柴达木盆地西部地下卤水水化学特征及成因分析[J].盐湖研究,2006,14(4):26-32.
[6] 樊启顺,马海州,谭红兵,等.柴达木盆地西部卤水特征及成因探讨[J].地球化学,2007,36(6):601-611.
[7] 樊启顺,马海州,谭红兵,等.柴达木盆地西部卤水水化学特征与找钾研究[J].地球学报,2007,28(5):446-455.
[8] 中国科学院青海盐湖研究所.卤水和盐的分析方法[M].北京:科学出版社,1988:29-237.
[9] 瓦良亚什科M T.钾盐矿床形成的地球化学规律[M].范立,译.北京:中国工业出版社,1965:30-57.
[10] White D E,Hem J D,Waring G A.Data of geochemistry—chemical composition of surface waters[M].Washington:United States Go-vernment Printing Office,1963:1-67.
[11] Kharaka Y K,Law D M,et al.Role of organic species dissolved in formation water from sedimentary basins inmineral diagenesis[J].Role of organic Matt er in Sediment Diagenests,1986,38:111-122.
[12] 林晓英,曾溅辉,杨海军,等.塔里木盆地哈得逊油田石炭系地层水化学特征及成因[J].现代地质,2012,26(2):377-383.
[13] 汪蕴璞.深层卤水形成问题及研究方法[M].北京:地质出版社,1982:68-69.
[14] 汪蕴璞.深层卤水形成问题及其研究方法[M].北京:地质出版社,1982:67-74.
[15] Craig H.Isotopic variations in meteoric waters [J].Science,1961,133(3465):1702-1703.