北京地区地热水氘过量参数特征分析  

Characteristics of deuterium excess parameters of geothermal water in Beijing

作　　者：刘凯[1] 刘颖超[1] 孙颖[1] 刘久荣[1] 王树芳[1] 刘宗明[1] 

机构地区：[1]北京市水文地质工程地质大队,北京100195

出　　处：《中国地质》2015年第6期2029-2035,共7页Geology in China

基　　金：中国地质调查局项目"全国地热资源调查评价-北京市地热资源现状调查评价与区划"(水[2013]01-029-006)资助

摘　　要：文章通过80组不同地热田的样品,分析总结了北京地区地热水资源氘过量参数的特征:(1)地热水的平均δ值为5.4,常温地下水的平均d值为6.04,热水的d值与氚值都较低,水岩作用所导致的氧同位素交换比冷水更容易进行;(2)地下热水的氢和氧同位素组成具有明显的热交换趋势,d值随地下水年龄增大而递增,当地热水年龄为(12.76±0.13)ka时,d值为11.2,而当地热水年龄为(38.96±0.63)ka,d值为14.6;(3)在同一地区,d值随着地下水埋深加大而减小,埋深为125.13 m时d值为5.72,埋深为3221 m时,d值为3.03;(4)从补给源到排泄区,地下水的d值应逐渐降低,其中北部补给区平均d值为7.31,北京断陷盆地平均d值为5.68,南部凤河营地区仅为-9.20;补给源区与排泄区水的d的差值越大,地下水的运动速度越慢;(5)当Eh小于200 m V时,北京地区地下热水的d值随着Eh值的降低而减少,如在桐热-7中,氧化还原电位为-326 m V,d值为-9.20,而在TR-43中氧化还原电位为158 m V,d值为7.48;当Eh大于200 m V时,地下热水的d值随着Eh值的降低而增加,但增幅较小。Eighty water samples were collected from different geothermal fields in Beijing and the following five kinds of characteristics of deuterium excess parameters were analyzed：（1） The average d value of geothermal water is 5.40, the average d value of cold groundwater is 6.04, which is bigger than that of the geothermal water, so the oxygen isotope exchange caused by water-rock interaction is easier in geothermal water than in cold groundwater.（2） The oxygen isotope has remarkable isotope exchange process, and the d value increases with the age of the geothermal groundwater. When the age of the water is（12.76±0.13） ka, the d value is 11.2; when the age of the water is（38.96 ± 0.63） ka, the d value is 14.6.（3） The d value decreases with the depth of the geothermal groundwater in the same area; when the depth is 3221 m, the d value is 3.03; when the depth is 125.13 m, the d value is5.72.（4） The d value decreases from the recharge area to the discharge area. The average d value is 7.31 in northern recharge area,5.68 in Beijing depression, and- 9.20 at the southern edge of Beijing plain. The velocity of flow decreases with the difference dvalues.（5） The d value increases with the redox potential when it is smaller than 200 m V. When the redox potential is-326 m V, the d value is-9.20; when the redox potential is 158 m V, the d value is 7.48. The d value decreases with the redox potential when it is bigger than 200 m V.

关 键 词：氘过量参数 地热水 氧同位素 氢同位素 氧化还原电位 

分 类 号：P314.1[天文地球—固体地球物理学]