Identified the hydrochemical and the sulfur cycle process in subsidence area of Pingyu mining area using multi-isotopes combined with hydrochemistry methods

Groundwater serves as an important water source for residents in and around mining areas.To achieve scientific planning and efficient utilization of water resources in mining areas,it is essential to figure out the chemical formation process and the ground water sulfur cycle that transpire after the coal mining activities.Based on studies of hydrochemistry and D,^(18)O-H_(2)O,^(34)S-SO_(4)isotopes,this study applied principal component analysis,ion ratio and other methods in its attempts to reveal the hydrogeochemical action and sulfur cycle in the subsidence area of Pingyu mining area.The study discovered that,in the studied area,precipitation provides the major supply of groundwater and the main water chemistry effects are dominated by oxidation dissolution of sulfide minerals as well as the dissolution of carbonate and silicate rocks.The sulfate in groundwater primarily originates from oxidation and dissolution of sulfide minerals in coal-bearing strata and human activities.The mixed sulfate formed by the oxidation of sulfide minerals and by human activities continuously recharges the groundwater,promoting the dissolution of carbonate rock and silicate rock in the process.

Investigation of Geographical Origin and Production Method of L（＋）-Tartaric Acid by Isotopic Analyses with Chemometrics

The determination of the geographical origin as well as the adulteration of natural products is a technical problem due to similar chemical composition between an adulterant and the original. It is assumed that tartaric acid comes from natural sources, however there is no specific regulation for this claim. This paper describes the use of isotope mass spectrometry associated with chemometrics to classify different samples of tartaric acid. The results showed that the variables δ^13C, δ^18O and δ^2H allowed the discrimination of tartaric acid samples by geographical origin and production method. By using a combination of chemometfic analysis it was possible to confirm a notoriousseparation of the samples. Thus, this is a promising method to be applied in the quality control and authenticity of tartaric acid.

Assessment of sources and transformation of nitrate in the alluvial-pluvial fan region of north China using a multi-isotope approach

A multi-isotope approach and mixing model were combined to identify spatial and seasonal variations of sources,and their proportional contribution to nitrate in the Hutuo River alluvial-pluvial fan region.The results showed that the NO3- concentration was significantly higher in the Hutuo River valley plain(178.7 mg/L) region than that in the upper and central pluvial fans of the Hutuo River(82.1 mg/L and 71.0 mg/L,respectively)and in the river(17.0 mg/L).Different land use types had no significant effect on the groundwater nitrate concentration.Based on a multi-isotope approach,we confirmed that the main sources of groundwater nitrate in different land use areas were domestic sewage and manure,followed by soil nitrogen,ammonia fertilizer,nitrate fertilizer and rainwater,and there were no significant spatial or seasonal variations.Combining δ^15N-NO3,δ^18O-NO3- and δ^37Cl results can increase the accuracy of traceability.Nitrification could be the most important nitrogen migration and transformation process,and denitrification did not significantly affected the isotopic composition of the nitrate.The SIAR model outputs revealed that the main nitrate pollution sources in groundwater and river water were domestic sewage and manure,accounting for 55.9%-61.0% and 22.6%(dry season),50.3%-60.4% and 34.1%(transition season),42.7%-47.6% and 35.6%(wet season 2016) and 45.9%-46.7% and 38.4%(wet season 2017),respectively.This work suggests that the random discharge and disposal of domestic sewage and manure should be the first target for control in order to prevent further nitrate contamination of the water environment.

Multi-isotopic system geochronology of low temperature eclogite from Huangzhen,Southern Dabie Terrain

Zircon U-Pb thermal ionization mass-spectrometer (TIMS) and secondary ion mass-spectrometer (SIMS) dating, mica and amphibole 40Ar-39Ar dating and mineral Sm-Nd isotopic compositions of Huangzhen low temperature eclogite and country granitic gneiss are carried out. The zircon U-Pb weighted average SIMS age is (231.6?9.7) Ma for one eclogite. The mica 40Ar-39Ar isochron age is (232.6?2.1) Ma and the lowest plateau age is (221.7?2.4) Ma from same sample. U-Pb TIMS concordant ages from other eclogite zircons are from (221.3?1.4) Ma to (222.5?2.3) Ma. U-Pb SIMS low intercept age from country granitic gneiss is (221?35) Ma. The retrograde amphibole 40Ar-39Ar isochron age is (205.9?1.0) Ma. Except for mica, which may contain excess 40Ar, all the ages represent peak and retrograde metamorphism of low temperature eclogites. It is indicated that the Huangzhen low temperature eclogites differ from Xiongdian low temperature eclogites of north of the Northern Dabie Terrain in metamorphic ages. Huangzhen low temperature eclogites share one coherent HP-UHP terrain with high temperature eclogites from Southern Dabie Terrain and they may have differences in subduction depth and cooling rates during exhumation.