| Gushan deposit is a representative Fe deposit in Ningwu ore concentration areawhich is one of the most important ore districts of the Middle-Lower Reaches ofYangtze River metallogenic belt. Based on the field work, this paper focus on varioustypes of ore, carried out petrographic analysis, electron microprobe analysis, rareearth elements analysis, fluid inclusion study, reman spectrum of inclusions, hydrogenand oxygen isotope analysis. We have studied the geological, geochemical,metallogenic fluid and genesis characteristics of the Gushan deposit. The mainconclusion are as follows:1. The magnetite formation of the Gushan deposit is divided into three stages,namely, disseminated magnetite, magnetite in breccia, ore pulp filling andhydrothermal vein magnetite. The ore pulp filling stage is the main ore-forming stageand is characterized by vesiculate structure, flow structure and cage structure.2. The electron microprobe analysis of magnetites in different types of ore showsthat the genesis of magnetites belongs to ultramaifc-mafic-neutral magmatic type.3. Fluid inclusions in apatites homogenize at average temperature about271.9℃.Coexistence phenomenon of liquid, gas and melt inclusions in apatites shows that theore-forming fluid belongs to early magmatic fluid or magmatic-hydrothermaltransition fluid.4. H, O isotopic compositions of fluid inclusions indicate that ore-forming fluiddominated by magmatic water or by mixing magmatic and meteoric water.5. The fluid inclusions of apatite are riched in H2O, CO2, hematite, magnetite,calcite and diopside, by Inclusions Raman testting.6. The REE characteristics of the apatite was significantly higher than the ΣREE(1919.3×10-6) of apatite in hydrothermal deposits. The ore-forming fluids of theGushan iron deposit are from the magmatic differentiation or early magmatic-hydrothermal transition stage.7. The genesis of Gushan Fe deposit which was under the influence of volcanismis dominated by ore-magma type. |
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