辽东古元古代富镁质碳酸盐岩建造菱镁矿滑石矿床成矿流体研究

The Minerogenic Fluids of Magnesite and Talc Deposits in the Paleoproterozoic Mg-rich Carbonate Formations in Eastern Liaoning Province

辽东地区古元古代大石桥组中分布有富镁质碳酸盐岩建造,并产有大型或超大型菱镁矿、滑石矿床。笔者等近期在该地区野外工作中发现了沉积型石膏岩,并对其和菱镁矿滑石围岩进行了相应的稳定同位素和流体包裹体研究。稳定同位素分析结果为δ^(13)C一般-1.8‰～+1.2‰、δ^(18)O 10‰～20‰,δ^(34)S(VCDT)23.9‰～26.5‰;结合菱镁矿和白云岩流体包裹体形态和成分特征,笔者等认为早期镁质非金属矿床的形成与古元古代的海相蒸发岩系有关,古海水演化而来的变质成矿流体对后期滑石矿床的形成起着重要的控制作用。

A lot of large to giant magnesite and talc deposits located in Mg-rich carbonate formations distributed in the Paleoproterozoic Dashiqiao Formation in eastern Liaoning Province, China. Writers, based their recent field work and study on stable isotopic geochemistry (δ13C=-1.8‰~ +1.2‰,δ18O=10‰~20‰, and 34SVCDT = 23. 9‰~26. 5‰) and fluid inclusions, present that the early formation of magnesite and magnesian deposits was dominated by evaporation and sedimentation in marine face while the later mineralization of talc deposits was controlled by the SiO2-rich and high salinity metamorphic fluids from buried paleaoseawater in a favorable environment.