基于反向地球化学模拟技术的深层地下水^(14)C年龄校正——以挠力河以北典型水流路径为例

^(14)C Age Correction of Deep Groundwater Based on Inverse Geochemical Modeling: a Case in the North of Naoliriver

地下水年龄的确定是水循环研究的重要内容,也是估计地下水水循环速度和定量评价地下水可更新能力的重要依据。以挠力河流域以北地区为例,利用反向水文地球化学模拟技术,识别出影响研究区内深层地下水地球化学演化的主要作用,并进行深层地下水^(14)C年龄的校正。研究认为,控制挠力河流域南部湿地区深层地下水化学演化的主要反应为方解石、黑云母、二氧化碳的溶解反应、高岭土的沉淀反应以及Ca-Na阳离子的交换反应;北部农业区主要发生了黑云母、二氧化碳的溶解及高岭土、方解石的沉淀和Ca-Na阳离子的交换反应。地下水^(14)C年龄校正结果表明,北部农业区深层地下水^(14)C年龄(9176a)明显老于南部湿地区(6097a),年龄校正结果与Vogel统计模型^(14)C年龄校正结果较接近。南部湿地区地下水循环速率为11.16 m/a,北部农业区地下水循环速率为2.19 m/a。研究结果对研究区地下水资源评价和制定农业区和湿地区地下水合理开发利用模式具有重要借鉴意义。

The determination of the groundwater age is not only an important content of the water cycle research,but also a significant basis to estimate groundwater circulation speed and quantitative-ly evaluate groundwater renewable ability. With region north of Naoli River Watershed as an example,inverse hydrogeochemical simulation technology was used to identify the main effects on geochemical evolution of deep groundwater area and conducts the14 C age correction of deep groundwater. The study suggests that the main reactions dominating hydrogeochemical evolutions of the deep groundwater in the south humid region of Naoli River watershed were that the dissolution of calcite,biotite and carbon dioxide and the precipitation of kaolinite and Ca-Na exchange. The main reactions dominating hydrogeochemical evolution of the deep groundwater in the agricultural area of the north of Naoli River watershed were that the dissolution of biotite and carbon dioxide; Ca-Na exchange and the precipitation of kaolinite and calcite. The14 C age correction results of deep groundwater showed that14 C age of deep groundwater of the north argriculture region（ 9 176 a） was obviously older than that of the south wet region in this study area（ 6 097a）. And the model corrective results of14 C age were close to age-adjusted results of Vogel model. The groundwater circulation rate of the south humid region in this study area was 11. 16 m / a,and the groundwater circulation rate of the north argriculture area was 2. 19 m / a. The results have important significance for the evaluation of groundwater resources and the reasonable development and utilization of groundwater of agriculture and wet region in this study area.