Preliminary Research Of The Serpentinized Marbles In Halaganlawusu Area, Inner Mongolia

Based on researches on Wulashan Group high-grade metamorphic rocks in Halaganlawusu area in Inner Mongolia Province in recent years, widespread serpentinized marbles exited in this region, which had obviously different rock composition with the gneisses, granulites and plagioclase amphibolite. Therefore, study on serpentinized marbles help restore the original rock of Wulashan Group and enhance the understanding of the ore-forming process.The rock is gray to yellow-green, porphyritic metacryst texture and mainly thick layered-massive structure, locally characterized by cataclastic structure. The groundmass is made up of medium-fine grained subhedral metacryst textured calcite. Porphyroblasts are mostly forsterite and diopside, of which forsterite and calcite inclusions enclosed in it constitute the enclosed metacryst texture. The major minerals include calcite (50-70%), serpentinized forsterite (25-40%), and secondary minerals are diopside (5-15%) and little amount of phlogopite (2-8%).Major elements geochemistry analysis showed that the rock was characterized by CaO, MgO and LOI enrichment, for instance (CaO+MgO) up to 47.72% and low CaO/MgO ratio (1.27-2.28), which suggested features of carbonatite. Combining the mineral assemblage and structures of recrystallization and deformation seen in the thin section, and multiple protolith recovery diagram results, the protoliths of the serpentinized marbles in Halaganlawusu area were silica contained dolostone and dolostone.Based on major elements analysis, the following conclusions can be drawn: the serpentinized marbles in Halaganlawusu area were Material source of the serpentinized marbles in Halaganlawusu area were formed by the marine sedimentation. Rock were formed in the closed basin having barrier island in dry weather conditions, showing the characteristics of epicontinental sea.