Study On Geochemical Characteristics And The Source Of Ore-forming Material Analysis Of No. 9 Metallogenic Belt In The Mianhuakeng Deposit, Northern Guangdong

The Mianhuakeng uranium deposit is located in the southeastern granite which is from the southeastern part of the Zhuguang area in the northern Guangdong Province.And in terms of the tectonic structure,it situates the junction of the post-Guangdong uplift and the Xiangxi-Guangxi-Haixi-Indosinian sag.In order to clarify the geological characteristics of the No.9 belt,summarize the rule of geochemical spatial distribution of the alteration elements in the No.9 belt,and analyze and discuss the source of its uranium,this paper,based on the detailed field geological survey,collected relevant research samples and carried out research methods such as rock ore petrography,element geochemistry and C-O isotope analysis.This paper has mainly gained the following aspects:(1)The formation of No.9 ore belt in the Mianhuakeng deposit is controlled by the tectonic alteration zone,and the ore body of the No.9 ore belt mainly presents the vein-like,lenticular or lenticular shape in the tectonic alteration zone.The segregation of ore is more obvious and the most of them are red silicified fractured rock type(also known as reddening type),red microcrystalline quartzite type(also known as silicified belt type)and white carbonate type;The surrounding rock alteration has zoning characteristics.In addition to silicification,carbonation,fluorite,and pyrite mineralization,the altered clay minerals are mainly mixed with illite and illite-montmorillonite.The layer is dominant,followed by chlorite and so on,and both of the altered mineral types and mineral combinations have similarities.(2)In the analysis of the spatial variation characteristics of element No.9 alteration zone,the process of ore-forming fluids show that various elements has regular changes : HREE shows a trend of increasing with the increase of U content,which presumes the action process of ore-forming fluid;U and HREE show similar geochemical behaviors and geochemical properties of Nb and Ta,Zr and Hf elements are synchronic,which speculates that ore-forming fluids have intrinsic genetic relationship with or similar to the source area,and its regularity space.At the same time,The regular space changing characteristics are indicative of mining.Combination with the phenomenon of peaking in strong alteration zone indicates that the vicinity of the strong alteration zone is an important Fluid metallogenic geochemical interface.(3)Combining the U and Th correlation characteristics and element traces in the altered zone indicates that the uranium in the mineralization is not derived from the alteration activation of the granite,however,it is from the fluid itself which is consistent with the fluid source.And the trace element tracer shows that the ore-forming fluid has the characteristics of shell-and-shell mixing.The study result concerning the carbon isotope of calcite in the ore-forming period of the Miankeng uranium deposit is basically consistent with the range of ?13CPDB in the ore-forming period of the ore-forming period,which consistently reflects the carbon properties of the mantle source,and the situation of uranium ore-forming fluids from the Zhuguang area,the evidence of Speculation related to mantle sources provides favorable.