Sedimentary Environment And Geochemistry Of The Kunyang Phosphorite Deposit In Yunnan Province

Phosphorus is vital to body composition elements, it is also very important for crop growth, therefore phosphorus has important significance for agricultural production. Secondly phosphorus as animal feed additive, in order to make animal effective absorption of calcium to promote bone growth. Moreover, in the modern light industry, chemical industry, metallurgy industry, sunderban, national defense industry etc, phosphorus also has extensive and important purposes.China is a large agricultural nation, the gap between food production and demand is gradually expanding.If phosphate rock can longendure stable supply the needs of phosphate production is related to the sustainable development of China's agriculture and the national food safety.To solve grain safety problems have important practical significance.This thesis is based on yunnan phosphate mining resources reserves and resources evaluation analysis.We study and analyse the sedimentary environment and the geochemical of Kunyang phosphorite deposit in the Yunnan province. The development of Kunyang district formation is completed,since proterozoic to Cenozoic,especially the strata in the upper Sinian system and the lower Cambrian. We study pre-ordovician phosphorous, including phosphorous pre-ordovician stratigraphic age, forming paleogeographic environment, sedimentary build, sedimentary spinning back, etc.According to data, the district in the south and west is primarily the upper Sinian system Kunyang formation, in northern and eastern is primarily the strata in Sinian system and Paleozoic.It also have some strata in Mesozoic and Cenozoic.Kunyang phosphorite deposit in the east of eastern Yunnan province is a large-scale marine sedimentary phosphor deposit, tectonically located at the southwestern margin of the Yangtze paleoblock. Lower Cambrian Qiongzhusi group ((?)₁³q) outcropping widely in the mining area constitutes the hanging wall rocks, which are also phosphor-bearing sedimentary formation; Zhongyicun group ((?)₁²z) containing phosphoric sedimentary formation; and Xiao waitoushan group ((?)₁¹x) the footwall of P-bearing sedimentary formation. The Dengying group (Zbdn) of Sinian System constitutes the Cambrian sedimentary basement, within which erosion planes present. This indicates that the phosphoric rock formed at the early transgression cyclic deposition during the global warming period. Phosphorite sedimentary rock is characterized by well-developed lenticular tidal bedding, and ripple mark and desiccation crack are very common. Ore minerals occur as spherical oolite texture, showing the feature of colloform deposition. Ore minerals are predominantly comprised of amorphous collophanite. Ore composition and lithochemical analysis show that the ore consists mainly of fluor-apatite and carbonatic minerals such as high-Mg dolomite and silicatic detrial minerals. P-bearing rock series is characterized by high contents of rare earth elements and uranium, distinct negative Ce anomaly in REE distribution diagram of phosphorite ores, and positive relation between REE enrichment and Fe₂O₃, strongly suggesting an environment of shallow oxidation deposition. All these features indicate that P-bearing sedimentary formation formed mainly in a littoral area containing supratidal, intertidal and subtidal shallow zones. Therefore, the deposit formed mainly in a sedimentary environment of either stable platform margin or a shallow continental shelf.