WU Yao-ye, XI Ai-hua*, GE Yu-hui , ZHONG Xiang

(School of Geoscience and Technology, Southwest Petroleum University, Chengdu 610500, China)

Abstract: The Mesozoic volcanic activity and metallogenesis occurred strongly and complicatedly in the Shaolanghe metallogenic belt of the Chifeng area in Inner Mongolia, as the belt was influenced by the North China Plate, the Xilamulun River Fault, the Chifeng-Kaiyuan Fault and the Nenjiang Fault. The Huanghuagou deposit is a typical Pb-Zn-Ag polymetallic deposit in the Shaolanghe metallogenic belt. The ore bodies are mainly hosted in the Late Paleozoic and Mesozoic volcanic lavas and pyroclastic rocks. According to the spatial distribution, ore bodies of the deposit can be classified into two types: 1) The vein-type orebody filling into radial fissures/fractures in volcanic crater; 2) The breccia-type orebody existed in the volcanic vent. Microscopic observation, EDS and electron microprobe micro analysis (EPMA) show that main metallic minerals of the deposit include galena, sphalerite, pyrite, psilomelane, etc., with minor rhodochrosite, pyrolusite, argentite and chalcopyrite. The main alteration mineral assemblages are quartz-chalcedony, adularia-illite-sericite, barite-fluorite, and siderite-rhodochrosite. Ores have veining, stockwork, banded, disseminated, pectinating, lamellar and brecciated structures, etc. There is mainly metasomatic gradient relationship between orebodies and wallrocks, with minor crosscutting relation by the vein. The characteristics of metallic minerals and altered wall rocks show that the deposit is characterized with those of the low sulfidation epithermal deposit. Combining with previous achievements, it is inferred that the deposit may be of epithermal genesis.

Keywords: Epithermal deposit; Huanghuagou polymetallic deposit; The Shaolanghe metallogenic belt; Chifeng of Inner Mongolia

ACTA MINERALOGICA SINICA Vol. 39, No.3, 2019, page 295-304