Abstract:Geochemistry of minor elements has already gained acceptance as an important indicator in the study of depositional environments, formation conditions and evolution of the saline deposit. Nevertheless, only by looking combinedly into both saline minerals and clays associated with them can better knowledge be acquired. This paper presents some results obtained in this aspect through the research into the Tertiary saline formation of Q basin, Hubei province. The geochemical characteristics of bromine and rubidium from saline minerals have been investigated. The resulting analytical data show that clear distinction exists between these minerals and marine saline minerals in bromine/chlorine coefficient. This suggests that the deposition of saline formation of q group was confined to a continental basin with soluble salts accumulated steadily within this relatively large enclosed lake basin. In this paper, depositional process of the whole Q group and the favorable layers for the deposition of K-Mg salts have also been approached in terms of distribution characteristics of Br/Cl coefficient, on which paragenetic association and origin of saline minerals have been elucidated tentatively. As is shown by the study of its geochemical behavior, rubidium is intimately correlated with potassium minerals, thus serves to be a geochemical indicator for potassium sediments; rubidium iri halite, however, can hardly be used as an indicator in the study of this mineral. The geochemical behavior of boron and lithium in clay sediments have been discussed in the second half of this paper with more emphasis on the former element. The boron content in the clay fraction and in the unfractionated whole rock sample indicates that the distribution characteristics of this element either in the whole saline formation or in individual sedimentary cycles are extremely helpful to the study of the variation of palaeosalinity of the lake basin during the process of deposition, thus serving as a remedy for the limitation of bromine geochemistry which is effective only for salts, and making it possible for the author to acquire a more comprehensive understanding of the depositional evolution. The study of lithium shows that the variation of its content in sedimentary cycles bear resemblance to that of the Br/Cl coefficient, and also has something to do with the salinity of the depositional environment. As a geochemical indicator, however, it is not so desirable as bromine or boron and requires further improvement.
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吴必豪，渠洁瑜，王弭力，黄良汉，祁佐明.1983.湖北Q凹陷第三纪含盐系Br、Rb、B、Li的地球化学研究[J].矿床地质,2(1):76~86.1983.Geochemistry of Br, Rb, B and Li in the tertiary saline formation of basin Q, Hubei Province[J].Mineral Deposits2(1):76~86
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