Abstract

Outstanding structures in the Hoành Sơn area consist of Mesozoic grabens developed upon the transformed Paleozoic folded basement. In these structures, gold mineralization includes two types, namely: quartz-gold-polymetallic sulphide (with the amount of sulphide ~20%) and quartz-gold - sulphide-poor (with the amount of sulphide ~3%) types. The gold mineralization is closely controlled by graben structures, especially anticlines in grabens, Middle Triassic volcanic-subvolcanic-hypabyssal structures in grabens and NW-SE trending fault and fissure systems.