Abstract:

The Haoyaoerhudong gold deposit is located in the west of the Mesoproterozoic Bayan Obo rift on the west section of the northern margin of the North China Platform. A lot of granitoid plutons and dykes appear in the interior and outskirts of the diggings mainly including quartz monzodiorite, monzonitic granite and alkali feldspar granite whose enclaves are named as monzogabbro. By analyzing the characteristics of petrography and petrogeochemistry, combining with the intrusion era of the same type plutons in the same region, the Haoyaoer-hudong pluton was considered to be formed in the syn-collisional and post-collisional environment of North China Plate and Siberia Plate. Among them, the monzonitic granite formed in syn-collisional environment, and is possibly influenced by the heat of melting of the underthrust plate and mantle wedge in the process of subduction, of which the parental magma derived from partial melting of lower crust; the quartz monzodiorite formed in the uplift environment of post-collisional, resulting from the melt of the thickening lower crust; the alkali feldspar granite belongs to the series of A-type granites of the late orogenic era when the mantle basaltic magma underplated leading to the lower crust melting and being mixed. Combing with the mineralization ages, the characteristics of the mineralization fluid and organic geochemistry of host rocks, the invasion of pluton is considered to offer essential heat and part of ore-forming fluid sources.

Key words: granitoid pluton, lithogeochemical characteristics, tectonic environment, Haoyaoerhudong gold deposit;Inner Mongolia