昌都地区盐泉水化学特征与找钾研究

Hydrochemical Characteristics of Salt Spring and Potassium prospecting in Changdu Basin

中文关键词:  昌都盆地  找钾  盐泉水  水化学特征  水化学系数

英文关键词::Changdu Basin  Potassium prospecting  Salt spring  Hydrochemical characteristics of salt spring  Hydrochemical coefficient

中文摘要:

      昌都地区发育有大量的膏盐、白云石及菱镁矿,研究其区域成钾潜力意义重大。在对昌都盆地蒸发岩矿点实地考察过程中,共采集12个盐泉水样及2个泉水样。通过常微量元素及水化学特征系数研究,查明研究区盐泉水水化学类型为氯化物型和硫酸钠亚型,属于岩盐溶滤成因,溶滤了大量的石盐和少量的碳酸盐岩及硫酸盐岩,纳西盐井盐泉水同时还受深部循环水的影响。昌都地区盐泉水样中Na、Cl含量及矿化度由北向南逐渐降低,Br、Li、B含量较低,整体上呈现以贡觉为中心,向北、向南逐渐增高的变化趋势。研究区盐泉水具有内陆盐湖性质,北部含盐地层更具海相成因特征,盆地由北至南从海相沉积环境逐渐过渡为内陆海沉积环境,受陆表水影响愈大。研究表明,类乌齐含盐地层经历了最强烈的浓缩蒸发及岩盐溶滤作用,其浓缩阶段晚于纳西及贡觉含盐带,其成钾潜力同样也优于纳西及贡觉含盐带,可作为钾盐矿异常点。贡觉和纳西含盐地层在不同程度上受到了陆表水的影响。综合对比前人研究成果,发现囊谦—昌都—兰坪盆地自北向南,成钾潜力逐渐变优。

英文摘要:

      :There is a lot of sulfate, dolomite and magnesite in Changdu Basin of Tibet. It is of great significance to study the formation -potash potential of this area. The authors collected 12 salt spring samples and 2 spring samples during the process of evaporites mines investigation in Changdu Basin. Study results of hydrochemical characteristics show that salt spring samples are mainly about chloride type and Sodium sulfate sub type, the formation of salt spring waters seem to be attributed to eluviation brine of halite ,and these salt spring are also leached by small amounts of carbonate rock and sulfate salt rock. The salt spring samples of Naxi are influenced by deep circulating brine at the same time as well. The degree of salt spring concentration such as Cl,Na and salinity show that the trend of brine concentration in Changdu basin was gradually reduced from north to south, their contents of Br, Li, B was gradually increased from Gongjue to north, and it also increased from Gongjue to south.The salt spring samples has the nature of the inland salt lake in study area. There is a tendency that marine sedimentary environment transition into interior sea sedimentary environment gradually from north to south in Changdu Basin, the northern salt belt has strong marine characteristics and the southern salt belt has surface water impact. The studies show that the saliferous formation of Leiwuqi has experienced the most intense evaporation, concentration and eluviation, the stage of brine concentration in Leiwuqi Salt belt was previous to the Naxi and Gongjue Salt belt, and the ore forming environment in the Leiwuqi Salt belt is better than the Naxi and Gongjue Salt belt. The Gongjue area can be considered to be one of the most promising areas in search for potash ore. The salt spring samples of Naxi and Gongjue was influenced by land surface waters. All of these evidences suggest that the potassium forming prospect of Nangqian Changdu Lanping Basin became gradually better from north to south.