Tietangdong breccia, Yixingzhai Au-Ag deposit, Fanshi Co., Xinzhou, Shanxi, Chinai

Regional Level Types
Tietangdong breccia	Deposit
Yixingzhai Au-Ag deposit	Deposit
Fanshi Co.	County
Xinzhou	Prefecture-level City
Shanxi	Province
China	Country

The Tietangdong breccia pipe is the most gold-rich breccia pipe (~20 t Au). Previous works have suggested a skarn crypto-explosive origin for Tietangdong based on samples collected from the shallow part of the breccia pipe. Analyzed zoning textures within garnet and epidote grains, inferring several magmatic–hydrothermal pulses and multiple crypto-explosion events in Tietangdong.

Breccia is mainly developed in the Tietangdong breccia pipe, and chlorite of boulders can be seen within the breccia. The alteration characteristics in
the mining area are pronounced, with sericitization generally developed, as well as silicification, hematite mineralization, epidotization, chloritization, carbonation.

The Tietangdong cryptovolcanic breccia pipe is exposed in the central part of the mining area, located at the intersection of three fault systems. It covers a surface area of approximately 0.05 km2, exhibits a funnel-shaped, pipe-like morphology, and dips at an angle greater than 80°. The breccia pipe exhibits a vertically zoned lithological profile. The 510 m level is characterized by silica-cemented gneiss breccia, while the 770 m level consists of marble with chlorite–pyrite alteration and local sulfide–quartz veins. The 830 m level exposes gabbro intruded by pyrite and quartz–pyrite veins. Skarn development is prominent at the 1070 m level along the felsite–marble breccia contact, marked by an assemblage of garnet, epidote, chlorite, and pyrite. Furthermore, euhedral garnets are present within local epidote skarn at this level. An outer annular structure surrounding the surface expression of the pipe is infilled with quartz porphyry, while an inner annular zone hosts gold mineralization. The core of the pipe at its top is characterized by a magnetite and specularite iron ore body. Towards the pipe’s margins, the lithology transitions inward from fractured and cataclastic rock to cryptovolcanic breccia cemented by skarn mineral associations.

Other Regions, Features and Areas containing this locality

References