Sulfur And Its Isotope Study On Taiyuan Formation Karstic Aquifer System In Huaibei Plain

Huaibei Plain is an important area of coal resources in our country, and mainlycontains four aquifers as follows: the Cenozoic fourth aquifer; the Permian coal seriessandstone fissure aquifer; the Carboniferous Taiyuan formation limestone karstic aquifer;and the Ordovician limestone karst aquifer.In this paper, the Carboniferous Taiyuan formation limestone karstic aquifer is theresearch object. The tendency between SO42-concentration and the geologicalenvironment is summarized by analyzing and comparing the chemical characteristicsfrom different mining area. The relationship between SO42-concentration, δ34S and theclosure is then explored after the sulfur isotope text of the groundwater, combining thewater chemical characteristics.Through the indoor cultivation of sulfate reducing bacteria, SO42-concentration,HCO3-concentration and ORP is tested with the passage of time to observe the processof bacterial sulfate reduction. Based on the fractionation effect of sulfate reduction, thedifferences of δ34S between groundwater and rocks in different positions and differentkarst aquifers is explained by several reasons.In the groundwater sulfate&sulfide system, the underground environment isdivided into two types: open and closed. When the groundwater is open, the δ34S valueof product H2S is lower than that of groundwater sulfate, and the SO42-concentration ishigher; while the environment is closed, the sulfate cannot be promptly added withbacterial sulfate reduction, so the SO42-concentration is lower as the δ34S value ofresidual sulfate and later period sulfide is higher.Compared to Paner coalmine and Panbei coalmine, the Taiyuan formationlimestone karstic aquifer of Juji coalmine and Liuer coalmine is more open, so the δ34Svalue of groundwater is lower and the SO42-concentration is higher. While in theHuainan coalfield, because of the tectonic movement, overlying rocks and the thrustfaults of Bagong Mountain and Minglong Mountain make the groundwater environmentin Paner coalmine and Panbei coalmine more closed. Among all the mines, the Taiyuanlimestone karstic aquifer in Paner coalmine is the most closed, therefore the δ34S valueof groundwater is the lowest and the SO42-concentration is the highest.