CAI Guo-sheng1, GUN Ming-shan1, DU Lin1, ZENG Dao-suo1, YE Lin2
(1. Institute of geology and mineral resources exploration, Non-Ferrous Metals and Nuclear Industry Geological Exploration Bureau of Guizhou, Guiyang 550005, China;
2. State key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China)
Abstract: The Yadu-Mangdong Pb-Zn metallogenic belt is an important part in the Sichuan－Yunnan－Guizhou metallogenic province. In recent years, with the discovery of the Super-large scale Zhugongtang Pb-Zn deposit, it has been become one of the geological and geochemical research focuses. In the paper, based on the comprehensive analysis of previously accumulated data of geological exploration, and the combination of latest geological prospecting and research results in the area, we have carried out a comparative study on the occurrence characteristics and hosting positions of Pb-Zn orebodies, and have summarized the ore-forming regularity and prospecting criteria of Pb-Zn orebodies in order to provide practical evidences for further prospecting Pb-Zn resources in the belt. The researches show that the Pb-Zn orebodies in the Yadu-Mangdong belt are hosted in the carbonate stratum under the Permian Emeishan basalt Formation. The different sized Pb-Zn deposits are mainly distributed in groups and belts along the Yadu-Mangdong fault zone. The straight distances between orebodies and the major fault (Yadu-Mangdong fault F1) are normally less than 1 km. The major fault (F1), ‘thrust fault-fold’ system, and secondary faults are favorable spaces for the Pb-Zn enrichment and mineralization. Especially, the occurrences of Pb-Zn orebodies are controlled by the ‘fold + axial faulting’ structural system, ‘major fault + homodromous secondary faults’ system, and ‘interlaminar fractures, fracture zones, and Karst caves’, etc. Furthermore, the Pb-Zn orebodies in the belt are hosted mainly in the major fracture zone and its footwall rocks (mostly in carbonates), which were obviously controlled by the interface of Si-Ca, with a small number of Pb-Zn orebodies hosted in the interlaminar fractures. In particular, The dominant alterations are the ‘high carbonaceous-argillaceous squeezing alteration’ and ‘ferromanganese carbonation’ for wallrocks close to Pb-Zn orebodies in the belt. It is suggested that there is a good potential for prospecting Pb-Zn resources in the depths of known Pb-Zn deposits, including the Yadu, Shaojiwan, Liangyan deposits, and the Banbianjie area in the southern part of F1 in the Yadu－Mangdong metallogenic belt.
Keywords: The Yadu-Mangdong fault zone; major fault; metallogenic characteristics of Pb-Zn deposits in the northwestern Guizhou; the Si-Ca interface; ore-controlling factors; indicator for prospecting mineral resources
ACTA MINERALOGICA SINICA Vol. 40, No.4, 2020, page 376-384
