泸州-开江古隆起对川东三叠纪成盐成钾环境的控制作用

摘要

泸州-开江古隆起的活动对早中三叠世川东盐类矿床的形成具有重要影响。本文通过川东三叠纪不同成盐阶段古构造特征、石盐及杂卤石的分布和古隆起不同位置含盐系的岩性组合对比等综合研究发现，古隆起相对周缘地形较高，其内部及边缘发育的小盐洼（如长寿地区）由于其水浅、盆小、蒸发速率快，有利于卤水浓缩形成原生杂卤石，也是可溶性钾盐的潜力区；早中三叠世之间发生了大规模的火山活动，成钾的物质来源更加丰富，富钾、镁离子卤水迁移渗流至厚层膏岩层中形成次生杂卤石岩，形成该时期川东杂卤石广布，且范围明显超过石盐岩的格局。%Activity of Luzhou-Kaijiang paleouplift has an important influence on the formation of salt deposits in the Early Middle Triassic in eastern Sichuan.By studying ancient structural characteristics in different stages of salt forming,distribution of salt and polyhalite and the contrast of lithologic salt system in different locations of paleouplift in Triassic in eastern Sichuan,this article found:some samll salt depressions(such as Changshou area)were formed along edge and inside of the paleouplift as it was relatively high.So it was conducive to the formation of native polyhalite by brine concentrating as the small salt depressions have samller water deep and area and fast evaporation reat.The paleouplift is a potential area of soluble potassium also.As a massive volcanic activity occurred between Early and Middle Triassic,material sources of potassium were abundant.Brine flowed into thick gypsum rock and formed secondary polyhalite.So in this period the polyhalite were widespread and significantly abundant than halite in eastern Sichuan.