Pan Yanning, Dong Guochen, Tsunogae Toshiaki, Wang Peng, Li Xuefeng, Dong Pengsheng
School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing, 100083, China.
College of Geology and Environment, Xi'an University of Science and Technology, Xi'an, 710054, China.
Sci Rep. 2024 May 27;14(1):12110. doi: 10.1038/s41598-024-62120-0.
Copper mineralization in the Pulang (PL) porphyry deposit, Langdu (LD) porphyry-skarn deposit and Songnuo (SN) porphyry prospect in northwestern Yunnan, China, is closely related to the emplacement of quartz monzonite porphyries. The chemical compositions of biotite and apatite from those porphyries were analyzed to calculate the halogen fugacity and to constrain mineralized and barren porphyries. Our data show that biotites from the PL deposit have higher MgO, SiO, TiO and F contents than those from the LD deposit or SN prospect. Compared to those in the LD deposit and SN prospect, the Mg (atoms per formula unit (apfu)) and Al (apfu) value in biotite is greater, and the F content is greater and the SO and CeO/YO ratio in apatite are lower in the PL deposit. Ti-biotite thermometry and apatite-biotite geothermometry show that the crystallization temperature of biotite from the PL deposit is higher than that from the SN prospect or LD deposit. The results suggest that oxygen fugacity, magmatic sulfur, and HO contents cannot be used to efficiently distinguish the PL deposit from the LD deposit and SN prospect. However, the halogen chemistry of biotite from the PL deposit is distinctly different from that of the LD deposit or SN prospect according to the lower IV (F), indicating that mineralized quartz monzonite porphyries in the PL deposit formed during the late magmatic stage, which is in contrast to those in the LD deposit and SN prospect. The mineralized porphyries display a remarkable negative linear relationship (r = - 0.96) with the log (f HF/f HCl) and log (f HO/f HF) ratio, which can be used to distinguish the mineralized and barren porphyries. Compared with other typical porphyry Cu systems, there is a remarkable positive linear relationship between IV (Cl) and log (f HO/f HCl). In addition, the linear slope and intercept for log (f HO/f HCl) ratios and the IV (Cl) of biotite from the potassic and phyllic alteration zones are significantly greater than those from other porphyries.
中国云南西北部普朗（PL）斑岩型矿床、浪都（LD）斑岩-矽卡岩型矿床和松诺（SN）斑岩矿点的铜矿化与石英二长斑岩的侵位密切相关。分析了这些斑岩中黑云母和磷灰石的化学成分，以计算卤素逸度并区分矿化斑岩和无矿斑岩。我们的数据表明，PL矿床中的黑云母比LD矿床或SN矿点中的黑云母具有更高的MgO、SiO、TiO和F含量。与LD矿床和SN矿点相比，PL矿床中黑云母的Mg（每化学式单位原子数（apfu））和Al（apfu）值更大，F含量更高，磷灰石中的SO和CeO/YO比值更低。钛黑云母测温法和磷灰石-黑云母地热测温法表明，PL矿床中黑云母的结晶温度高于SN矿点或LD矿床中黑云母的结晶温度。结果表明，氧逸度、岩浆硫和H₂O含量不能有效地将PL矿床与LD矿床和SN矿点区分开来。然而，根据较低的IV（F），PL矿床中黑云母的卤素化学与LD矿床或SN矿点明显不同，这表明PL矿床中的矿化石英二长斑岩形成于岩浆晚期，这与LD矿床和SN矿点中的情况相反。矿化斑岩与log（fHF/fHCl）和log（fH₂O/fHF）比值呈现出显著的负线性关系（r = - 0.96），可用于区分矿化斑岩和无矿斑岩。与其他典型的斑岩型铜系统相比，IV（Cl）与log（fH₂O/fHCl）之间存在显著的正线性关系。此外，钾化和绢英岩化蚀变带中黑云母的log（fH₂O/fHCl）比值的线性斜率和截距以及IV（Cl）明显大于其他斑岩中的。
