四川德昌大陆槽稀土矿床地质特征

Geological characteristics of Dalucao REE deposit in Dechang County, Sichuan Province

为查明德昌大陆槽稀土矿床的成矿地质特征和稀土元素的赋存状态,通过对大量岩石、矿石光(薄)片的观察鉴定以及对矿体形态、矿石的物质组分、结构构造的研究,表明该矿床受喜马拉雅期富稀土碱性杂岩的构造控制,成矿地质特征与牦牛坪矿床极为相似。大陆槽稀土矿床为攀西稀土成矿带上最年轻的稀土矿床,矿床类型新,稀土品位高,主要稀土矿物氟碳铈矿粒度较粗,可选冶。

The discovery of the Dalucao REE deposit in Dechang County is a new achievement made by the No.109 Geological Party of Sichuan Bureau of Geology and Mineral Resources after the discovery of the Maoniuping REE deposit in Mianning County. In order to find out ore-forming geological characteristics and REE occurrence modes of the Dalucao REE deposit, the authors made observation on lots of rock and ore thin sections, and studied shapes of orebodies as well as material composition, textures and structures of ores. The results show that the Dalucao REE deposit is very similar to the Maoniuping REE deposit in such aspects as the NS ore-controlling structure of the Himalayan REE alkaline complex, the 'three-in-one' REE metallogenic model composed of small high-level aegirine-augite syenite porphyry intrusives, aegirine-augite fluorite Sr-barite veins and calcite veins, and metallogenic geological characteristics. The K-Ar age of the Dalicao deposit is 10.4 Ma, indicating the youngest REE deposit in the Panxi REE ore belt. The deposit is of a new type characterized by high REE grade. The main REE mineral bastnaesite has relatively coarse grains and is hence suitable for ore dressing.