Uranium Content And Its Control Mechanisms Of Alaer River Valley In Northwestern Qaidam Basin

The migration,existing form and enrichment law of elements is one of the key research points in elementary geochemistry.As the most heavy element found in nature so far,uranium has been studied by researchers in almost all aspects especially in its migration,enrichment in the water column and the influencing factors because of its unique properties.This paper,relying on the Applied Basic Research Project of Qinghai Science and Technology Department “the enrichment law of uranium in the Alar River and Gasikure Lake Basin and the assessment of uranium resource in brine” and the field work had done from April 2015 to June 2015.The measuring of main ion and uranium content in water was done in Salt lakes chemical analyzing and testing center,Qinghai institute of salt lakes,Chinese academy of science.This article mainly studied the uranium content and its influencing factors in the Alar River,the hydrochemical characteristics of the Gasikure Salt Lake which is fed by the Alar River and surrounding water.1.Rivers in the studying area are natural weak-alkaline low-salinity water and with the solute dissolved by the water continually,all the hydrochemical indicators increased gradually from upstream to downstream.The hydrochemical type of fresh water is hydrocarbonate water.Ions in river controlled by rock weathering;streams and springs in Gasi Basin have been significantly affected by the evaporation.Major ions in water are derived from halite,carbonates(calcite,dolomite),sulfate,etc.,and influenced by silicate mineral dissolution.2.Brine in the studying area is magnesium sulfate subtype brine.The intercrystalline brine in Basin,surface brine of Gasikure Salt Lake and the water from salt field are both affected at evaporation and salting process,the ion contents increase with the evaporation of brine.3.The distribution of uranium content in water is uneven: the uranium content rises with the distance from the mountain pass reducing;the uranium content of streams and springs in Gasikule basin is much higher than the river because of evaporation;the uranium content in the salt lake characterized by the high content in the edge and low content in the center because of the salt crystallization and water supply.The distribution of Uranium is irregular of the intercrystalline brine.4.Uranium in river is mainly from the source area,weathering and leaching of granite and metamorphic rock on both sides.Uranium in Gas Kure salt lake mainly comes from the river supply.5.Uranium content in water is mainly affected by the following factors in study area : the uranium content of source rocks,conductivity of water,water salinity,weathering and leaching of the carbonatite,evaporation,content of the organic matters and other factors(sedimentation,covering rate of the loess,content of the suspended matters in water and content of the microorganism).