Abstract:

 Changshanhao gold deposit is a large metamorphic microclastic rock type gold deposit hosted in carbonaceous slates and phyllites of the MesoNeoproterozoic Bilute Formation of Bayan Obo Group in central Inner Mongolia. The gold ore bodies are tabular and lenticular and no clear boundary to wall rocks; the ores occur as sulfur veinlets or quartzsulfide veinlets deformed with strata in beddings, joints and fractures, which consist of simple minerals with weak alterations. The ore and wall rocks have the similar trace element geochemical feature. The ranges of ore ²⁰⁸Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁶Pb/²⁰⁴Pb, close to those of strata, are 37.430 8 to 38.979 2， 15.452 2 to 15.674 1 and 17.109 to 18.921 7，respectively. Goldbearing quartz veins mainly contain liquid fluid inclusion with homogenization temperature of 230 to 370 ℃  and salinity of 6.01% to 20.52% NaCl eqv. δD and δ¹⁸O of the fluid are -108‰ to -112‰ and 6.4‰ to 9.4‰. These geologicalgeochemical characteristics indicate that oreforming material and fluid come from strata. The authors infer that Changshanhao gold deposit is a sedimentmetamorphism mesotherm deposit, and the later magmatic activity had a little effect on the metallogenesis.

Key words: gold deposit, geologicalgeochemical characteristic, sedimentmetamorphism, Changshanhao, Inner Mongolia