寒武系盐盆地的分布特征及其对中国成盐找钾的意义

 寒武系膏盐岩在世界范围内广泛分布,以亚洲寒武系分布最为广泛,含盐岩系主要分布在俄罗斯东西伯利亚、伊朗—印度—巴基斯坦—阿曼和中国.东西伯利亚、伊朗—印度—巴基斯坦均有钾盐发现.构造基底性质对钾盐盆地的形成具有关键性控制作用：稳定构造区在准稳定区有利聚钾;准稳定区在局部稳定构造区利于聚盐成钾,如形成于早寒武世的涅帕钾盐矿床——世界上大型钾盐矿之一,即位于前寒武纪地层为基底的古拗陷区.中国主要的古代盐盆地多发育于以前寒武纪为基底的准克拉通(陆块)中.近年来,随着油气勘查和盐业开发工作,中国上扬子陆块、华北陆块和塔里木陆块相继发现了4个大型的膏盐岩盆地.上扬子陆块与塔里木陆块发现单层厚度较大的岩盐沉积及较好的成钾水化学显示,为在中国寒武系蒸发岩盆地开展成盐找钾工作提供了重要依据.

Distribution of Cambrian Salt Basin and Its Significance for Halite and Potash Explorations in China

The wide distribution of the Cambrian rock gypsum and salt is an important feature of older strata in Asia. The Cambrian salt-bearing sequences are mainly distributed in East Siberia of Russia, Iran, Oman, India, Pakistan, and China. Potash salts are also found in East Siberia, Iran, India, and Pakistan. The nature of the tectonic basement is a key controlling factor for the formation of potash basins. The stable tectonic region is favorable for the potash concentration in a quasi-stable region, and the quasi-stability is favorable for the salt concentration and the potash formation in a local stable tectonic region. For example, one of the largest potash deposits in the world--the Siberian Nepa potash deposit-was formed in the Early Cambrian in the palae-depression of Precambrian strata. China's major ancient saline basins are in quasi-cratons (continental block) with the Precambrian basement. In China, only one solid potash deposit in Yunnan can be exploited. However, there are a number of marine evaporite basins, so the study of marine evaporite basins is an important way to solve the problem of serious shortages of potash in China. In recent years, with the exploration of oil and natural gas and the development of the salt industry in China, the drilling has uncovered extensive gypsum and salt deposits in Cambrian strata. Four large marine evaporite basins were found in China. In this paper, through the lithofacies-paleogeographic analysis and the potash geological survey, extensive thick rock salt deposits are found in the Yangtze block and the Tarim block, where good and pronounced anomalies of high Br/Cl and K/Cl coefficients were identified. The Chengkou-Wuxi area of the Yangtze and the Tazhong area of the Tarim block are important areas for potash explorations in the Cambrian, and merit a further study. They provide some important information for carrying out the halite and potash explorations in Cambrian evaporite basins in China.