江西赣州盆地盐湖型锂矿地质特征及找矿前景

赣州盆地位于南岭EW向复杂构造带东段北侧,其展布受NE向构造控制,晚白垩世红层发育良好,是华南东部具有代表性的红盆。该盆地总体为一个封闭的倾向南东的箕状湖盆,盆地外围加里东晚期、燕山早期第二阶段、第三阶段和燕山晚期岩浆岩中富集Li,晚白垩世周田组砂质岩石中Li含量较高。勘查成果显示,该盆地已发现盐湖型锂矿的线索,在潭口周边区域揭露到含水层厚17~37 m、LiCl含量188~457 mg/L的含锂卤水层。位于盆地沉积中心的晚白垩世周田组中部,紫红色、褐紫色细砂岩、灰褐色细砂岩夹粉砂岩、紫红色粉砂岩是主要的含矿层位。盐湖型锂矿的主要找矿标志是:呈浅红色调、紫红色调的遥感影像;层状封闭的低阻异常;高氯、低钾、低溴的水地球化学异常;断裂影响小的凹陷盆地沉积中心以及周田组中部的细碎屑岩。通过与吉泰盆地和会昌盆地进行对比,发现该盆地盐湖型锂矿资源潜力较大,找矿前景较好,加强综合找矿可望实现新的突破。

Geological characteristics and prospecting potential of brine-type lithium ores in Ganzhou Basin,Jiangxi Province

Ganzhou Basin, located on the north side of the eastern part of the EW-trending complex tectonic belt in Nanling Range, China, is controlled by the NE-trending structure. With well-developed late Cretaceous red beds in the region, it has been a representative red basin in the eastern part of South China. The basin is basically a closed south-east-inclined dustpan-like lake basin, with Li enriched in magmatic rocks of the Late Caledonian, stage II and III of Early Yanshanian and Late Yanshanian, and high Li content in sandy rocks of the Late Cretaceous Zhoutian Formation in the periphery of the basin. The exploration results indicate clues of brine-type lithium ores found in the basin, revealing a lithium-bearing brine layer with aquifer thickness of 17~37 m and LiCl content of 188~457 mg/L in Tankou surrounding area. The major lithium-bearing layer is in the middle of the Late Cretaceous Zhoutian Formation located in the sedimentary center of the basin, dominated by purple red and brownish purple fine sandstone, gray-brown fine sandstone interspersed with siltstone, and purple red siltstone. The main prospecting signs of lithium brine include remote sensing image of light red tone and purple red tone, stratiform closed low resistance anomaly, water geochemical anomaly of high chlorine, low potassium and low bromine, the sedimentary center of depression basin under less fracture influence and fine clastic rock in the middle of Zhoutian Formation. Compared with Jitai Basin and Huichang Basin, brine-type lithium resources in this basin are found to have a great potential and good prospecting prospect. It is expected to achieve a new breakthrough by strengthening comprehensive prospecting.