论中华麦饭石的地学特征

GEOLOGICAL CHARACTERISTICS ON CHINA MAIFANSHI(MEDICAL STONE)

本文对中华麦饭石的岩石学、岩石化学、微量元素地球化学、REE地球化学、岩石物理化学特征以及形成条件和成因机制等进行了较全面的地学研究,为今后麦饭石的开发、应用提供了重要的信息资料。

Through geological investigation, the authors believe that the China Maifanshi (medical stone) belongs to a hypabyssal small intrusion of rectaalkali biotite quartz-monzonite porphyry. It is the I-type granitic body formedfrom the syntectic granitic magma emplacing in the Mesozoic faulted basins in the Yanshan tectonic-magmatic cycle. SiO_2=58.43％—61.78％, Al_2O_3=17.02％—18.53％, K_2O+Na_2O=7.58％—8.50％; δ=3, SI<10—12, DI>62; ΣREE=221.87—275.58×10^(-6). ΣCe/Σr=0.87, δEu=1.05—1.10, indicating a distribution pattern of H ΣREE-depletion. The content of Zn (the useful element) in the China medical stone is three times over the Clarke value.The content of Cd (the main harmful element) is one tenth of the Clarke value in the same-type of rocks.The available mineral with useful elements is high in solubleness.The infusion reaches the national standard for potable water. The medical stone possesses a high adsorbability either for harmful elements or for pathogenic bacteria.