六盘山地区泉水地球化学特征

摘要/Abstract

摘要： 根据六盘山地区泉水的化学组成和氢、氧同位素数据, 讨论了该区地下水的化学类型、成因及其动态变化特征。 2012年11月和2014年7月在六盘山地区采集10处泉水样品, 氢氧同位素由液态水同位素分析仪测定, 离子组分浓度由离子色谱和化学滴定法测定。水样的TDS范围为218~27508 mg/L, δ¹⁸O和δD值分别为-12.0‰~ -8.5‰, -88.5‰ ~-61.3‰。 δ¹⁸O和δD指示该区泉水来源于大气降水, 并受水循环条件及水岩反应程度的影响。根据舒卡列夫分类法, 所采水样可划分为10种水化学类型, 受含水层岩性控制, 宁南地区的水化类型主要为SO₄-Na型, 渭北西部地区的水化类型主要为HCO₃-Ca·Mg型。两次所采水样的离子浓度显示多数水样点的HCO^-₃具有夏高冬低的季节性变化特征, 千川村(QC)、双井村(SJ)等因含水层赋存环境较封闭, 受降水干扰小; 硝口村(XKH)泉水的离子毫克当量比值变幅最大, 说明该泉点水岩反应程度变化较大, 易受断层带活动的影响。研究结果确定了六盘山地区水文地球化学背景和水的来源, 为该区流体地球化学地震监测、预测提供了背景资料。

关键词: 水文地球化学, 离子浓度, 氢氧同位素, 六盘山地区

Abstract: The origin and formation processes of the spring water from the fault zones in the Liupan Mountain and vicinity were discussed based on hydrochemical and isotopic data. We collected 10 water samples from springs and wells near the Liupan Mountain fault zones in November 2012 and July 2014. The attained hydrochemical data show that the TDS values ranged from 218 mg/L to 27508 mg/L, Values of δ¹⁸O and δD ranged from -12.02‰ to -8.47‰ and -88.5‰ to -61.33‰ respectively, which indicated that the spring waters in this area are mainly of meteoric origin and affected by the conditions of hydrological cycle and water-rock interaction. There are 10 hydrochemical types in the research areas based on the Schukalev hydrochemical classification method. Controlled by the aquifer lithology, the water samples in the sounthern area of Ningxia were mainly characterized by SO₄-Na type, while that in the northwest region of Weihe river were mainly characterized by HCO₃-Ca·Mg type. Ratios of ion concentrations between 2012 and 2014 indicated that Mg²⁺、 HCO^-₃♂、 F^- had obvious variations, maybe influenced by season. Underground waters in sampling point SWT、SG have significant interference by rainfall and surface water, while those of the sampling point WM、 QC 、 DYZ etc. have less interference because of the relatively closed aquifer. Ion milliequivalent ratio of XKH spring show the biggest variation and an opposite trend to the seasonal effection, which may indicate that this spring had more changes in water-rock reaction and are more susceptible to the variations of the chemical information from the internal fault. Through the sample data collected in different seasons, the hydrogeochemical background of Liupan Mountain was determined and the local control and influence factors of fluid geochemistry were analyzed in this paper. The results provide the fluid geochemical characteristics and are in favor of seismic monitoring and forecasting.

Key words: Spring water, Ion concentration, H and O isotopes, Hydrochemistry, Liupan Mountain

中图分类号:

P315.7

李静,李营,陆丽娜,孙凤霞,谢超,崔月菊. 六盘山地区泉水地球化学特征[J]. 地震, 2017, 37(1): 61-72.

LI Jing,LI Ying,LU Li-na,SUN Feng-xia,XIE Chao,CUI Yue-ju. Geochemistry of Spring Water in the Liupan Mountain Area[J]. EARTHQUAKE, 2017, 37(1): 61-72.

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