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贵州织金磷矿为一超大型含稀土磷矿床,产于早寒武世梅树村期底部含磷岩系。本文在分析该磷矿矿石化学组成、矿物组合的基础上,重点针对磷块岩的结构特征进行扫描电子显微镜和电子探针微区分析,发现在纵向上:上段硅质磷块岩结构类型包含泥晶结构、内碎屑结构、无定形结构和少量生物屑结构,其结构成熟度较低,沉积水体较深,属于宁静的半局限海/浅海沉积环境;而下段白云质磷块岩结构类型包含内碎屑、无定形结构和较多生物屑结构,其结构成熟度较高,水动力作用较强,沉积水体较浅,属于动荡的滨海沉积环境。横向上,织金戈仲伍组与滇东渔户村组大海段在地层年代上相互对应,两处的磷块岩系所含的结构类型相似,只是各种结构类型所占比例不同。此外,结合其他沉积环境指标,发现织金磷矿沉积于弱氧化―贫氧的滨海向浅海过渡的环境。
Guizhou Zhijin phosphate rock is an ultra-large rare earth-bearing phosphate deposit that was produced at the bottom of the Early Cambrian Pishucun period. Based on the analysis of the chemical composition and mineral assemblage of this phosphate rock, the paper focuses on the structural features of the phosphate rock by scanning electron microscopy and electron probe microanalysis. It is found that in the longitudinal direction, the structure type of the upper siliceous phosphorite rock contains The mudstone structure, the internal debris structure, the amorphous structure and the small amount of biological debris structure. The structure maturity is low and the sedimentary water body is deep, which belongs to the semi-confined sea / shallow sea sedimentary environment. Containing internal debris, amorphous structure and more biological debris structure, the structure of high maturity, strong hydrodynamic, shallow sedimentary water, belong to the turbulent coastal sedimentary environment. Laterally, the Zhuguang-Zhongwu Formation and the Dadong-Dafuhai Formation correspond to each other in the stratigraphic age. The two types of phosphate rock blocks contain similar types of structures, except that the proportions of various types of structures are different. In addition, in combination with other indicators of sedimentary environment, we found that the deposition of weaving phosphate rock in the environment of weak oxidation - poor oxygen transition from coastal to shallow sea.