沂源土门岩溶发育机理与含水系统的水文地球化学特征

Mechanism of Karstic Development and Hydro-geochemical Characteristics of Tumen in Yiyuan County

山东沂源土门岩溶含水系统,位于半干旱半湿润气候带。区内山青、水秀、洞密、林茂、古文化璀璨。别具特色的三水转化关系使区内大气降水、地表水、岩溶地下水的化学成分及空间变化颇具规律。来自岩溶含水系统边界以外变质岩分布区的外源水和大气降水渗入地下,对系统内的碳酸盐岩具有较强的溶蚀能力,当达到饱和甚至过饱和时又以泉水的形式溢出地表流出系统外。在漫长的地质岁月中,溶蚀—溢出—再溶蚀—再溢出,周而复始,于是形成了沂源土门别具一格的岩溶地貌景观。

Water-bearing system in Tumen of Yiyuan county locates in semi-arid-semi-humid climate zone. There are green mountains, beautiful rivers, numberous caves, luxury forests and brilliant and ancient culture in this region. The unique three-water conversion relation causes the chemical composition and spatial variation of atmospheric water, superficial water and karstic groundwater become very regular. Allogenic water from metamorphic rock distribution area which is beyond karstic water-bearing system and atmospheric water infiltrated intosurfacem, which has rather strong solution to carbonate rock inside the system. When it reaches saturation or over-saturation, they will spill out of the surface as the form of springs. During the long geological history, solution-spill-resolution-respill form the unique karstic landform at Tumen of Yiyuan county.