Research On Geochemistry Characteristics And Cause Of Formation Of Jingxiang Phosphorus Deposit In Hubei, China

Hubei Jingxiang phosphorus deposit which located in western Hubei metallogenic belt of the northeastern part of the upper Yangtze block, characterized by large, rich taste and high quality is one of the important producing phosphate areas of China. It can better reveal the distribution rule and ore-controlling factors of Hubei Jingxiang phosphorus deposit by doing restoration works on depositional environment and paleogeographic structure of that time. Deep research on local geochemistry and cause of formation of phosphorus deposit is significant to metallogenic period accurate forecast, evaluation of mineral prospection, guidance for perambulation and discovery of potential mineral resources.According to Literature of Jing Xiang region and research on mineralize section plane of Huji mining site, from bottom to top, there are 4 phosphorus layers: the first phosphate layer (Ph1), inequality grain dolomite; the second phosphate layer (Ph2), soil phosphorus calcarenite dolomite; the third phosphate layer (Ph3), fine powder dolomite; the fourth phosphate layer (Ph4), clay-powder dolomite, all of that constitute the three sedimentary cycles. The first phosphate layer corresponds to the first cycle of sedimentation while the second and third phosphate layer corresponds to the second cycle of sedimentation and the fourth phosphate layer corresponds to the third sedimentary cycle. Above shows a characteristic that Jingxiang phosphorus deposit owns industrial phosphorite with multi-layer structure.Based on X-ray diffraction analysis to ore and identification under the microscope, it shows that phosphorite ore consists mainly of micritic apatite, dolomite, quartz, chalcedony, clay minerals and a small amount of calcite and pyrite.Geochemical characteristics of Ore and rock samples around show a fact that this region belongs to a kind of relative oxydic briny depositional environment. And it also holds a characteristic of hydrothermal sedimentary rock.Characteristic ratios of trace elements and REE distribution patterns also show diversified sedimentary environments of different seams (Ph1, Ph3).According to the genesis of phosphorite, by analyzing sedimentary structures and depositional environment of the Jingxiang phosphate, lithofacies palaeogeography and biological effect, its causes can be summarized as: Jingxiang phosphate belongs to a kind of closed or semi-enclosed shallow sedimentary deposits which deposited then enriched at uplift section in shallow water. It is directly or indirectly impacted by biological effects.