氯化物型钾盐矿床氯同位素地球化学的初步研究

根据国内外许多钾盐矿床大量样品测定的结果，通常石盐（岩）的３７Ｃｌ／３５Ｃｌ比值和δ３７Ｃｌ值高于钾石盐（岩），而钾石盐（岩）又高于光卤石（岩），说明这些蒸发岩是在不同水体、不同浓缩阶段形成的，是氯同位素分馏作用长期进行的结果。这些蒸发岩的氯同位素组成与其Ｂｒ、Ｋ、Ｍｇ含量变化有密切关系。今后在我国找钾过程中，应把氯同位素组成及其Ｂｒ、Ｋ、Ｍｇ含量结合起来，作为找钾标志考虑。

A PRELIMINARY INVESTIGATION ON STABLE ISOTOPIC GEOCHEMISTRY OF CHLORINE FOR THE POTASH DEPOSITS OF CHLORIDE TYPE

ccording to the analyzed results of samples from many potash deposits at home and abroad, generally, halite(halitite) is >sylvite(sylvitite)>carnallite(carnallitite)in their 37 Cl/ 35 Cl ratios and δ 37 Cl(%) values. For example, to the potash deposit of the Catalonia Basin of Spain, the 37 Cl/ 35 Cl ratio and δ 37 Cl(%) value in halite are 0 31958～0 31941 and 0 1002% ～0 0475%; in sylvite are 0 31913 and -0 0407%; in carnallite are 0 31887 and -0 1221%, etc.. It illustrates that these evaporites are formed in the different water bodies of various concentrating stages and result from the long term fractionation of chlorine isotopes. The chlorine isotopic composition for those evaporites is closely associated with their contents of Br, K and Mg. Therefore, the authors suggest to take the chlorine isotopic composition and their contents of Br, K and Mg as the indicators for exploring the potash deposits in China in the near future.