昌乐玄武岩内刚玉巨晶（蓝宝石）中发现富碳酸盐和硫酸盐熔融包裹体及其意义

Corundum megacrysts (sapphires) hosted by Changle Cenozoic basalts of Shandong Piovince wntain various melt inclusions, whose comlxsitions are of significance in understanding the mantle metasomatism beneath the North China Craton and the parent magma of the corundum megacrysts. Based on petrographic observation and detailed laser Raman analysis, the authors identified two types of melt inclusions: one is primary melt inclusion rich in carbonates and sulfates and the other is secondary melt inclusion containing sulfates and chloride, with CO2 and H20 existent in both of them. This is the first time that sulfate and carbonate are recognized in fluid/melt inclusions from basalt-hosted corudum megacrysts. The compositions, combined with existing isotopic compositons of noble gases and microthermometry of the inclusions, imply that they are a kind of carbonatite that propably originated from metasomatized mantle. The authors thus hold that the mantle beneath the North China Craton might have experienced metasomatism of carbonates and sulfates-bearing melts (carbonititic magma) besides silicic melts. The carbonates and sulfates identifed in primary inclusions suggest that they must have played an important role in corundum crystallization. The corundums probably resulted from the interaction between mantle- derived carbonatites andsilicic magmas/rocks, and were transported to the surface by subsequent basaltic lava.