Material sources and genetic analysis of the iron-manganese carbonatite breccia host rock of the stratiform Pb-Zn-rich orebodies in the Lengshuikeng orefield

The Lengshuikeng orefield has a complex combination of shallow porphyry type orebody and deep stratiform orebody. The stratiform orebody is hosted in (Fe, Mn) carbonatite breccia layer which is sandwiched in crystal tuff of the Upper Jurassic Daguding Formation. This paper has discussed and analyzed the characteristics of Fe-Mn carbonatite breccia in the aspects of main material composition, trace elements composition, distribution, attitude and its relationship with the orebody on the basis of basic geological features of the Fe-Mn carbonatite breccia. In combination with X- ray powder analysis of minerals, carbon- oxygen isotopes and hydrogen-oxygen isotopic evidence, the authors have reached the conclusion that the Fe-Mn carbonatite breccia is of the deep lake facies volcanogene sedimentary origin closely associated with the formation of stratiform orebody, and the early volcanogene sedimentary carbonatite rock had been subjected to the superimposed reformation of later porphyry magma emplacement and fluid activity, which formed Zn-Ag-rich deposits genetically associated with porphyry.