Soil water stable isotope characteristics of different reclamation aged soil in Dongtan Coal Mining subsidence area in Shandong Province,China

Analysis of the variation characteristics of different water bodies is a basis of applying isotopic technology in regional water cycle research.Dongtan coal mine is the first mine which produces more than one hundred millions of tonnes of coal in China.Long term exploitation in this area has already caused some surface subsidence problems which makes regional water cycle became more complex.In this study the authors took samples from soil water, surface water (lake and collapse pit water) and ground water (well water) and analyzed the characteristics and conversion features of δD and δ¹⁸O.The results show that the atmospheric precipitation was the main water source of soil and precipitation experienced strong evaporation during the replenishment course; the δD and δ¹⁸O of the upper soil water had a declined trend of δD and δ¹⁸O with the increase of reclamation time, while it had an increasing trend for the bottom soil water.Among the δD and δ¹⁸O of surface water (lake and collapse pit water), ground water with the δD and δ¹⁸O ofprecipitation, the δD and δ¹⁸O of the collapse pit water and of precipitation were very close, indicating that the collapse pit water mainly came from precipitation; whereas the δD and δ¹⁸O in lake and underground water (well water) were much more similar, indicating that the cracks in this study area were more likely to be the channels of surface water and deep ground water.