摘要
柴达木盆地是中生代开始拗陷的内陆山间断陷盆地,面积约90,000km^(2)。棋布于盆地的湖泊,按水的矿化度分为淡水湖、半咸水湖、咸水湖和盐湖四类。该盆地共有湖泊37个,其中,淡水湖1个、半咸水湖6个、咸水湖2个、盐湖28个(图1)。这些盐湖的平均海拔高程约2788.23m,湖水面积平均约46.45km^(2),湖水深度平均约0.742m。
In the Qaidam basin there are altogether 37 lakes:1 fresh-water lake,6 brackish-water lakes,2 saline-water lakes and 28 salt lakes.The pH value of salt-lake brines is 7.014 on the average,and the average total mineralization is 340.75 g/1.Their water-bodies belong mainly to the five-component eguilibrium system,Na-K-Mg//SO_(4).C1-H_(2)O,which can be further grouped into Na-Mg-SO_(4),Mg-SO_(4),transitional chloride and chloride types by their hydrochemical property.The salt-lake brines of the first salt-forming epoch(N_(2)-Q_(3))were of the sulphate type.In the second salt-forming epoch(Q_(3)-Q_(4)),some of them,however,turned to be of the chloride type.The pH value of brines decreases with the increase of total mineralization,that is,lower when the total mineralization is in range of 50-310 g/1,and higher in the range of 310-355 g/1.However,when the total mineralization is higher than 355 g/1,the pH value will decrease slowly again.Total mineralization of the chloride type and the transitory chloride subtype brine is higher than the sulphate type,being 310-530 g/1,310-470 g/1,and less than 355 g/1 in that order.Among the 40 chemical components found in the saline lake brine in Qaidam basin,potassium is mainly concentrated in the chloride type and transition subtype brine,boron and lithium are mainly concentrated in the sulphate type brine.Evaporation experiments show that boron and lithium are accumulated in concentrated brine until crystallization of bischofite takes place.It is the same with potassium before salt-formation,but its content decreases after the salt-formation.
作者
于昇松
Yu Shengsong(Institute of Salt Lake,Academia Sinica,Xining)
出处
《海洋与湖沼》
1984年第4期341-359,共19页
Oceanologia Et Limnologia Sinica
