华南地质2026，Vol.42Issue(4)：612-633,22.DOI:10.3969/j.issn.2097-0013.2026.04.005
锡石U-Pb年代学与微量元素约束湖南香花岭地区晚侏罗世锡矿化作用
Constraint of Cassiterite U-Pb Geochronology and Trace Element Geochemistry on the Late Jurassic Sn Mineralization in the Xianghualing Area,Hunan Province,South China
摘要
Abstract
[Objective]The Xianghualing ore field is an important tin polymetallic ore field in the middle segment of the Nanling metallogenic belt,where various types of granite-related mineralization are widely developed.Nevertheless,the metallogenic processes are not fully understood,warranting further investigation into the timing of Sn mineralization,the characteristics of ore-forming fluids,the occurrence and substitution mechanisms of trace elements in cassiterite,and the precipitation mechanisms of cassiterite.[Methods]In this study,we conducted systematic investigations on the tin mineralization in the Jianfengling pluton and the Nanjiling dike within this ore field,including petrography,cassiterite U-Pb dating,and trace element geoche-mistry.[Results]The result shows that the U-Pb ages of two Jianfengling cassiterite samples are 159.6 ± 3.1 Ma and 158.9 ± 7.8 Ma,respectively,and those of three Nanjiling cassiterite samples are 154.1 ± 4.8 Ma,156.4± 8.3 Ma,and 152.0 ± 11 Ma,indicating that tin mineralization in both bodies formed in the Late Jura-ssic(160～150 Ma).Trace element analysis shows that cassiterite from both deposits has low Zr/Hf ratios(<5),suggesting a genetic link to highly fractionated granites.Strong positive correlations among high field strength elements(Nb,Ta,Zr,Hf,U)indicate that the ore-forming fluid originated from a highly evolved magmatic system.Tetravalent ions(Zr4+,Hf4+,W4+,U4+)can directly substitute Sn4+into the cassiterite lattice;pentavalent ions(Nb5+,Ta5+)require coupled substitution with Fe3+((Nb,Ta)5+ + Fe3+ = 2Sn4+).The positive correlations between Fe-U and Fe-W suggest that U and W may occur in tetravalent form and enter the cassiterite lattice synergistically.Cassiterite grains show negative Eu anomalies,which may reflect a reduced ore-forming fluid environment or be inherited from a highly fractionated magmatic system;combined with previous fluid inclusion evidence,it is likely that phase separation occurred.[Conclusions]Combined with previous studies,we propose that cassiterite precipitation was controlled by multiple factors,including Sn-As redox reactions driven by short-lived cooling,water-rock reaction with carbonate wall rocks,and fluid boiling.Comprehensive research suggests that the Late Jurassic tin mineralization in the Xianghualing area is a direct product of the evolution of a highly fractionated granitic magmatic-hydrothermal system.关键词
南岭成矿带/香花岭矿田/尖峰岭/锡石U-Pb定年/锡石微量元素Key words
Nanling metallogenic belt/Xianghualing ore field/Jianfengling/cassiterite U-Pb dating/trace elements of Cassiterite分类
天文与地球科学引用本文复制引用
谢长明,王艳军,李凯旋,王大钊,陈永康,冷成彪..锡石U-Pb年代学与微量元素约束湖南香花岭地区晚侏罗世锡矿化作用[J].华南地质,2026,42(4):612-633,22.基金项目
深地国家科技重大专项(2025ZD1009303)、国家自然科学基金项目(42563011、42022021)、江西省自然科学基金(20252BAC240269)、江西省国家级高层次人才创新创业项目和江西省"双千计划"项目(DHSQT22021006) （2025ZD1009303）
