鄂尔多斯盆地盐池-定边地区水化学场分布特征及形成机理

DISTRIBUTION CHARACTERISTICS AND FORMATION MECHANISM OF HYDROCHEMICAL FIELD IN YANCHI-DINGBIAN AREA OF ORDOS BASIN

根据盐池-定边地区水化学场分布特征及其自然地理、地质构造、水文地质背景、岩相古地理和古水文地质条件,以水文地球化学理论为指导,采取野外水文地质调查、水样采集与测试及水文地球化学方法分析研究了该水化学场的形成机理及影响因素.研究表明,鄂尔多斯盆地盐池-定边地区水化学场分布主要有SO4·Cl-Na·Mg型、HCO3·SO4-Na型、HCO3·Cl-Na·Ca型和HCO3-Ca·Na型场,在白于山分水岭向北和西北的水平分带明显,水化学场与地下水流向呈逆向分布.本区水化学特征主要受古沉积中心及地层原始含盐量、地质构造、混合作用、地下水运动规律、古地下水等综合因素的影响.

According to the distribution characteristics of hydrochemical field in Yanchi-Dingbian area,as well as its geography,structure,hydrogeological background,lithofacies paleogeographical and paleohydrogeological conditions,guided by hydrogeochemical theory,the field hydrogeological survey,water sampling and testing and hydrogeochemical methods are used to analyze the formation mechanism and influencing factors of hydrochemical field.The results show that the hydrochemical fields mainly include SO4·Cl-Na·Mg,HCO3·SO4-Na,HCO3·Cl-Na·Ca and HCO3-Ca·Na types,with obvious horizontal zoning in the north and northwest of Baiyushan watershed,and the hydrochemical field and groundwater flow direction in reverse distribution.The hydrochemical characteristics of the area are affected by the comprehensive factors,mainly paleo-depocenter and initial salt content in strata,geological structure,migmatization,groundwater movement and fossil groundwater.