当前位置: X-MOL 学术Ore Geol. Rev. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Textural and chemical characteristics of beryl from the Baishawo Be-Li-Nb-Ta pegmatite deposit, Jiangnan Orogen: Implication for rare metal pegmatite genesis
Ore Geology Reviews ( IF 3.3 ) Pub Date : 2022-09-06 , DOI: 10.1016/j.oregeorev.2022.105094
Zhi-Wei Fan , Yi-Qu Xiong , Yong-Jun Shao , Chun-Hua Wen

The Baishawo pegmatite deposit is a newly discovered large Be-Li-Nb-Ta deposit, with estimated reserves of 16,160 t BeO @ 0.084 %, 11,280 t Li2O @ 0.85 %, and 3,450 t (Ta2O5 + Nb2O5) @ 0.201 %. The 3# pegmatite is internally zoned into border (contact against two-mica granite), wall, intermediate, and core zones. Beryl, the dominant economic mineral, occurs mainly in the intermediate and wall zones. In the intermediate zone, beryl coexists with feldspar and quartz, and in the wall zone, with quartz, tourmaline, garnet, and feldspar. Geological and petrographic observation, Electron-probe Microanalysis (EPMA), TESCAN Integrated Mineral Analyzer (TIMA), X-ray mapping, and Laser Ablation Inductive Coupled Plasma Mass Spectrometry (LA-ICP-MS) analysis were conducted to study the textural and compositional features of the beryl. The EPMA data show the concentrations of Al2O3, SiO2 and BeO in beryl are 17.61–18.32 wt.%, 64.01–65.23 wt.%, and 13.09–13.89 wt.% from the intermediate zone, respectively, and 17.57–18.52 wt.%, 64.33–65.15 wt.%, and 13.20–14.10 wt.% from the wall zone, respectively. Beryl from the intermediate zone contains higher concentrations of Ti (4.29–34.5 ppm), Mn (33.9–277 ppm), Rb (86.2–230 ppm), Cs (3333–4522 ppm) and Sn (0.571–28.7 ppm) than beryl from the wall zone (Ti 2.65–5.70 ppm, Mn 19.0–54.2 ppm, Rb 104–114 ppm, Cs 747–1242 ppm and Sn 0.085–1.26 ppm). Substitutions in beryl of the intermediate and wall zones are Li for Be, and Fe for Al. The distributions of alkali metals, Mg and Fe in beryl suggest that the pegmatite in the two beryl-bearing zones is the product of magmatic-hydrothermal interaction. Decreasing Mg content and Mg/Fe ratio with increasing Cs content and Cs/Na ratio suggest that beryl compositions reflect evolution of a highly differentiated two-mica granite magma, of which there is a residual fraction.



中文翻译:

江南造山带白沙窝Be-Li-Nb-Ta伟晶岩矿床绿柱石的结构和化学特征:对稀有金属伟晶岩成因的启示

白沙窝伟晶岩矿床是新发现的大型Be-Li-Nb-Ta矿床,估计储量为16160吨BeO@0.084%、11280吨Li 2 O@0.85%、3450吨(Ta 2 O 5  + Nb 2 O 5 )@ 0.201%。3 #伟晶岩在内部被划分为边界(与两个云母花岗岩接触)、壁、中间和核心区。绿柱石是主要的经济矿产,主要产于中间带和围壁带。中间带绿柱石与长石、石英共存,壁带与石英、电气石、石榴石、长石共存。进行地质和岩相观察、电子探针显微分析 (EPMA)、TESCAN 集成矿物分析仪 (TIMA)、X 射线绘图和激光烧蚀电感耦合等离子体质谱 (LA-ICP-MS) 分析,以研究结构和成分绿柱石的特征。EPMA 数据显示 Al 2 O 3、SiO 2的浓度绿柱石中的 BeO 和 BeO 分别为 17.61–18.32 wt.%、64.01–65.23 wt.% 和 13.09–13.89 wt.%,以及 17.57–18.52 wt.%、64.33–65.15 wt.% 和 13.20 –14.10 wt.% 分别来自墙区。来自中间区域的绿柱石含有比绿柱石更高浓度的 Ti (4.29–34.5 ppm)、Mn (33.9–277 ppm)、Rb (86.2–230 ppm)、Cs (3333–4522 ppm) 和 Sn (0.571–28.7 ppm)来自壁区(Ti 2.65–5.70 ppm,Mn 19.0–54.2 ppm,Rb 104–114 ppm,Cs 747–1242 ppm 和 Sn 0.085–1.26 ppm)。中间区和壁区绿柱石中的取代物是 Li 代替 Be,Fe 代替 Al。绿柱石中碱金属、镁和铁的分布表明,两个含绿柱石带的伟晶岩是岩浆-热液相互作用的产物。

更新日期:2022-09-06
down
wechat
bug