Mafic Geochemical Characteristics And Its Research Significance Of Xiangshan Uranium Ore-field,jiangxi Province

Xiangshan uranium ore-field deposit is located at Le’an county and Chongren countyintersection of Jiangxi Province, which is the largest volcanic type uranium deposit in thatfield of our country, and as one of the main base of uranium resources. Xiangshan uraniumore-field geological work of our predecessors to carry out a more comprehensive,The basicblank but for the study of mafic rocks. In this paper, Through the geological research onXiangshan mafic rocks in the field and Detailogy, etc. Found that the mafi-c at Xiangshanarea had two types: the internal of the ore field is the lamprophyre, the external substrate isthe diabase. ed study of the petrographic and geochemical characteristics indoor. Made thefollowing knowledge and results.（1）Through Research on the Mafic petrology and Mineral（2） The lamprophyre of the SiO2content are42.20%to54.20%,Rittmann index (σ)from1.38to8.21, Belong to the calc-alkaline to alkaline rock series; Trace elements andrare earths in general show a more consistent distribution patterns, are LREE enrichmentrightist-distribution patterns. The diabases of the SiO2content from50.20%to55.41%,Rittmann index (σ) are2.99~4.28, shows that the diabase samples belong to the calcal-kaline series; Trace elements and rare earths in general show a more consistent distrib utio-n patterns, Have shown that right wing type distribution patterns of LREE enrichment.（3） The87Sr/86Sr ratios and143Nd/144Nd ratios of the lamprophyre and diabasebetween the lower crust in the mantle to the mantle of eastern China mantle. Showed thatthe Xiangshan region of the lamprophyre and diabase magma source from the mantle,andcontaminated by crustal material. At the diagram of leadoftectonic model, the（207Pb/204Pband206Pb/204Pb）ratios of the data points of the lamprophyre and diabase all locatedbetween the lines of mantle and orogenic evolution, Also show that Mafic rocks andMagma source Consistent From the mantle, and contaminated by crustal material.（4）Through the K-Ar isotopic age determinations,There are three the role oflamprophyre invasive in Xiangshan ore field, Respectively: The first phase of134Ma, thesecond phase of120~125Ma, and the third of84.5Ma; There are two invasive role ofdiabase effect in the basement metamorphic rocks of the Xiangshan Periphery, Which thenorthern is149Ma, and the Southern is193Ma. （5）Consider that the tensional role of Pacific plate subduction and pull effect causedby constructed with re-activation is important influence on the formation at the Xiangshanmafic dikes.（6） It’s clear that Xiangshan mafic magmatism and uranium mineralizationobviously, and Xiangshan Uranium Mineralization has the characteristics of deepmineralization.