青海共和盆地塔秀滩富锶地下水分布特征及形成机制研究OA

Qinghai Province possesses abundant high-quality natural mineral water resources,particularly characterized by strontium-enriched mineral waters.However,previous studies have primarily focused on strontium-enriched water bodies in karst regions,with limited understanding of the hydrochemical characteristics,spatial distribution patterns of strontium,and enrichment mechanisms in pore-type strontium-enriched groundwater within unconsolidated rock formations.Therefore,the Taxiutan area in Qinghai's Gonghe Basin was selected as the research site,where 156 water samples and 38 rock and soil samples were collected.By comprehensively applying methods such as the Piper three-line diagram,Pearson correlation analysis,principal component analysis(PCA),and spatial interpolation,this study revealed the hydrochemical characteristics,spatiotemporal distribution patterns,and dominant formation mechanisms of strontium-enriched groundwater in loose rock formations.(1)The groundwater chemistry exhibits significant spatial differentiation,transitioning from an HCO3-Ca·Mg type in the foreland to HCO3·SO4-Ca·Mg type at the plain's edge,with median total dissolved solids(TDS)increasing from 113.65 to 352.95 mg/L.Strontium concentrations in groundwater increased along the runoff path from 0.11 mg/L in the recharge zone to 1.23 mg/L in the discharge zone,with high-strontium areas primarily distributed in the Xilongqu-Mangla River confluence zone.Temporally,groundwater strontium concentrations peaked during normal flow periods and were lowest during high-flow periods,whereas surface water concentrations peaked during low-flow periods.(2)Strontium in water primarily originates from Triassic limestone and Quaternary silt,with release mechanisms including the dissolution of carbonate and silicate minerals and cation exchange;On the groundwater system scale,strontium-enriched bedrock in the southern mountainous area releases strontium through dissolution.This strontium enters the loose aquifers of the plain via lateral groundwater recharge,where it undergoes further enrichment through cation exchange and retention processes,ultimately reaching peak concentrations in the foreland discharge zone.The distribution characteristics and formation mechanisms of strontium-enriched groundwater in porous loose rocks within the Gonghe Basin at the northeastern margin of the Qinghai-Xizang Plateau is elucidated.The findings provide a scientific basis for the exploration and sustainable development of this high-quality mineral water resource.The BRIEF REPORT is available for this paper at http://www.ykcs.ac.cn/en/article/doi/10.15898/j.ykcs.202508210222.