地球化学模拟在南北古脊梁岩溶裂隙水系统划分中的应用

Application of Geochemical Modeling in the Plotting of Karst Fissure Water Systems in the North-south Archaic Uplift, Ningxia, China

南北古脊梁是贺兰山经向构造体系的核心部分,为一条SN向的震旦系、寒武系、奥陶系地层隆起。寒武系、奥陶系地层主要为灰岩和白云岩,其间赋存有较丰富的岩溶裂隙水。由于埋深大,构造情况复杂,南北古脊梁的岩溶裂隙水的分布和径流规律至今仍不是十分清楚。本文利用地球化学模拟的方法,对南北古脊梁深埋岩溶裂隙水的系统划分和各部分之间的水力联系进行了研究。认为:系统Ⅰ和系统Ⅱ的边界应当在严湾和吕套之间,其边界为一条由第四系地下水补给形成的,地下水位较高的可移动地下分水岭;系统Ⅰ和系统Ⅲ之间存在水力联系,系统Ⅰ北端排泄口太阳泉的水量有46%来自系统Ⅲ的补给,在萌城泉和太阳泉之间可能存在一条导水断层形成的岩溶裂隙水的强径流带。

Northward archaic uplift is the central part of Helan Mountain Northward tectonic system, it＇s a uplift of Sinian, Cambrian, and Ordovician stratums. There is abundant karst fissure water in the limestone and dolomite of Cambrian and Ordovician. For the reason of deep embedding and complex tectonic condition, scatter and flow condition of the karst fissure water is still obscure. In this paper, geochemical modeling method was used to fix the border between karst fissure water systems and the relationship of diffe rent systems. The modeling results show that： the border between karst fissure water system I and Ⅱ is between Yanwan and Lvtao, the border is a moveable groundwater dividing crest, and is recharged by quaternary groundwater; There is maybe strong groundwater flow along a water conductive fault between Sun spring and Mengcheng spring, about 46% of the groundwater of Sun spring is from Mengcheng spring by the connection of this water conductive fault.