鄂尔多斯盆地北部白垩系地下水水化学特征及影响因素研究

Hydrochemical characteristics and influencing factors of cretaceous groundwater in the northern Ordos Basin

以2011～2017年在鄂尔多斯盆地北部施工的8个水文地质补充勘探项目(4个地区)为依托,对白垩系地下水水化学成果资料进行系统的整理分析,总结出地下水水化学特征的主要影响因素因素。研究结果表明,该地区气候条件自东南向西北具有明显的分带规律;保安群西侧(阻水边界)和北侧(隔水岩组)的断裂构造形成的阻水边界;白垩系含(隔)水层间地层在垂直与水平方向没有统一完整的隔水顶、底板;大致以安边—四十里梁—东胜梁地表分水岭为界,东侧地下水与上部以垂向积极交替循环为主;西侧地下水垂向水力联系减弱;白垩系砂岩孔隙—裂隙水地下水流由中部(地表分水岭)向东、北、西三个方向"背离式"径流;地表分水岭附近,受阳离子交替吸附作用影响;地表分水岭东侧,受溶滤作用、混合作用影响;西北部地区,因气候因素受蒸发—浓缩作用明显。

Based on the eight hydrogeological supplementary exploration projects(four areas)constructed in the northern part of Ordos Basin from 2011 to 2017 in four areas,systematically collating and analyzing the data of groundwater Hydrochemistry in Cretaceous,the main influencing factors of groundwater hydrochemistry characteristics were summarized as follows:Climate conditions with obvious zoned regularity from southeast to northwest;Water-blocking edge formed by fracture structures in the West(water-blocking boundary)and North(water-blocking rock group)of Baoan Group.There was no unified and complete water-proof roof and floor in the vertical and horizontal directions in the Cretaceous interlayer water-bearing strata;The surface watershed of Anbian-Shililiang-Dongshengliang was roughly bounded by the vertical active alternating circulation between the eastern groundwater and the upper part;the vertical hydraulic connection of the Western groundwater was weakened;Cretaceous sandstone pore,the groundwater flow of fissure-fissure water was "deviated" from the middle(surface watershed)to the east,north and west;near the surface watershed,it was affected by cation alternating adsorption;on the east side of the surface watershed,it was affected by leaching and mixing;and on the northwest,it was evaporated-concentrated due to climatic factors.