Geochemical Characteristics Of Field Rock Of Shituling Uranium Deposit In The Xiazhuang Uranium Orefield

Xiazhuang uranium ore fields is an important part of Nanling metallogenic belt with southeast end of Eurasia, the regional structure in the western edge of Cathaysia, This pluton regionally located at the cross of post Caledonian uplift of Fujian and Jiangxi province, and hollow zone of Hunan, Guizhou and north Guangdong province. Orefield located NEE huangpi Quartz fault zone and fault with horse feces holding area, located in China’s important collection of granite type uranium deposits in the region, is a typical granite uranium field。According to uranium mineralization and with granite-related hydrothermal uranium deposits can be divided into silicified-type, the intersection-type and phyllic alteration-type, which phyllic alteration-type proposed to identify a new type in recent years, The Shituling uranium deposits of Xiazhuang uranium ore fields is a typical representative, called the Shituling uranium deposits type.Shituling uranium deposits in the metallogenic time earlier(122 ~ 138Ma), metallogenic high temperature(290 ~ 338℃), rich ore grade(> 0.3%) and other characteristics,due to the attention of the educators of uranium geology, and is doing important types for future uranium deeply to find blind attack.Taking the Shituling uranium deposits as the research object, through geological characteristics within the mining field observations sheet microscopic identification, and for the cataclastic rocks(ore), alkali metasomatite rocks and the granite of near the orebody,We Determined the major、trace and rare earth elements compositions, to explore the uranium mineralization. The main conclusions are made as follows:⑴ On the alteration characteristics, the granite of near the orebody have a stronger potassium、 sodium metasomatism and muscovitization. There are weak hematitization、chloritization and sericitization alteration. The alkali metasomatite rocks also has the obvious hematitization、chloritization and sericitization alteration, based on the granite of near the orebody. the cataclastic rocks have the obvious phyllic alteration,as a result that rocks change compositions. Sericite and quartz is the main rock forming minerals⑵ Character of major、trace and rare earth elements of the granite of near the orebody 、 alkali metasomatite rocks and cataclastic rocks are basically the same. Reflecting the alteration is affected by the same, to suggest different alteration rocks fluid interaction results during the same period. The different alteration rocks could be caused by the faults zone before mineralized alteration.⑶ The granite of away from the orebody with a Si O2 range of 75.24% ~ 76.44%,the granite of near the orebody and the alkali metasomatite rocks with Si O2 were 62.9% ~ 72.4%, 65.5% ~ 71.9%, a large variation range of content,and significantly lower than the granite of away from the orebody. Show that the alkali metasomatism caused the obvious effect of rock to silicon, quartz content in the microscopically observed is consistent.but the cataclastic rocks(ore) with a more variable Si O2 was 65.7% ~ 78.9%, content of Si O2 were lower than as well as higher than the granite of away from the orebody.So in the process of alkali metasomatism,not the past what people think, silicon from removing Si effection taken out rocks to form silicified zone, but some silicon form a very fine quartz still remains in the rocks by recrystallization. This is consistent that strongly phyllic alteration rocks to precipitate a large number of quartz.⑷ the granite of near the orebody and the alkali metasomatite rocks with the content of K2O、Na2O and K2O+Na2O did not show significantly higher than The granite of away from the orebody, On the contrarily, some samples the content of Na2 O and K2O+ Na2 O is lower than them. Indicating that K and Na drag-in is not obvious in the process of mineralization, does not support the alkali metasomatism is the main reason of mineralization alteration.⑸ the granite of near the orebody the content of Fe O、Fe2O3 、Fe O+ Fe2O3 and Fe2O3/Fe O were 0.28% ~1.26%、0.03%~ 0.54%、0.31%~1.33% and 0.06 ~ 0.94. Compared with the far ore bearing granite, the near ore granite 、the alkali metasomatic rocks and the cataclastic rocks the content of Fe O、Fe2O3 、Fe O+ Fe2O3 and Fe2O3/Fe O showed a consistent increase, and Fe2O3 increased was more significant. Indicate Fe elements drag-in is obvious in the mineralization process, also support that hematite alteration is one of the main reasons for mineralization alteration.⑹ Compared with the far ore bearing granite, the near ore granite、the alkali metasomatic rocks and the cataclastic rocks the content of Ba、Th、U、La、Ce、Sr、Nd、Zr、Sm substantially grown, the content of Yb、Tm、Lu significantly reduced, the content of Rb、Li、Cs、Hf Little change. Instructions that mineralization fluid had higher Ba、Th、U、La、Ce、Sr、Nd、Zr、Sm content, lower Yb、Tm、Lu content.⑺ Compared with the far ore bearing granite, the near ore granite 、the alkali metasomatic rocks and the cataclastic rocks the content of ∑REE Increased significantly, and the increase was mainly LREE, LREE substantially join to, HREE is basically unchanged or slightly decreased. Negative Eu anomalies are significantly reduced, showed that in the process of uranium mineralization, the ore forming fluid which take place alkali metasomatism with fine grained two mica granite of Maofeng pluton, it should have the characteristics of LREE enrichment, Eu negative anomaly is weak.