现代地质2026，Vol.40Issue(2)：300-316,17.DOI:10.19657/j.geoscience.1000-8527.2025.079
诸广中部鹿井铀矿田大场坪矿点花岗岩成因及其对铀成矿的启示
Genesis of the Granite at the Dachangping Ore Deposit in the Lujing Uranium Ore Field,Central Zhuguang Area,and Its Implications for Uranium Mineralization
摘要
Abstract
Granite-related uranium deposits exhibit a close spatial and genetic association with granitic intru-sions.Investigating the relationship between magmatic evolution and uranium mineralization is essential for a deeper understanding of uranium metallogenic regularities and for elucidating the regional metallogenic mecha-nisms.At the Dachangping uranium deposit,the medium-to coarse-grained two-mica granite is the principal ore-hosting wall rock.In this study,drill core samples from various depths at Dachangping were analyzed using petrography,LA-ICP-MS zircon U-Pb dating,major and trace element geochemistry,and Sr-Nd isotopic compo-sitions to explore the magmatic evolution.Analytical results indicate that the crystallization age of the medium-to coarse-grained two-mica granite is(230.4±1.0)Ma.Geochemically,the granite is silica-rich,has a high to-tal alkali content with K＞Na,and a Rittmann index of less than 3.3,classifying it as a high-K calc-alkaline granite.With A/CNK values greater than 1,it belongs to the peraluminous granite category.Trace element data reveal enrichment in high field strength elements(HFSEs),such as Th and U,and significant depletion in large-ion lithophile elements(LILEs),including Ba and Sr.These granites are characterized by low Nb/Ta,high Rb/Sr,and high Rb/Nb ratios.Rare earth element(REE)patterns,normalized to chondrite,show a pro-nounced"seagull-shaped"distribution with a distinct negative Eu anomaly.In addition,the granite exhibits high initial 87Sr/86Sr ratios((87Sr/86Sr)i)and low εNd(t)values.These geochemical signatures are consistent with crust-derived granites and uranium-bearing granites in South China.Moreover,the granite displays low CaO/Na2O and CaO/Al2O3 ratios,along with a high(Na2O+K2O)/CaO ratio,indicating that the source re-gion was dominated by metamorphosed argillaceous-siliciclastic sedimentary rocks-characteristic of S-type gran-ites.Integrated with geochronological data and the regional tectonic framework,the formation of the medium-to coarse-grained two-mica granite is interpreted to have occurred shortly after the peak of the collision between the South China-Indochina block and the North China block.It was emplaced in a post-collisional extensional tec-tonic setting associated with crustal thickening and thinning,driven by a combination of radiogenic heat accumu-lation in the crust and thermal input from mantle-derived magmas.关键词
大场坪铀矿点/地球化学/S型花岗岩/富铀花岗岩/源岩特征/构造环境判别Key words
Dachangping Uranium Deposit/geochemistry/S-type granite/uranium-rich granite/source rock characteristics/tectonic discrimination分类
天文与地球科学引用本文复制引用
陈旺,夏菲,刘军港,钟福军,党飞鹏,李志鹏..诸广中部鹿井铀矿田大场坪矿点花岗岩成因及其对铀成矿的启示[J].现代地质,2026,40(2):300-316,17.基金项目
核技术研发科研项目(地H2301-2). （地H2301-2）
