Dissolution-collapse breccias in the Chaqupacha carbonate-hosted Pb-Zn deposit, Central Tibet

The Chaqupacha deposit, located in the Tuotuohe River area, central Tibet, contains an indicated Pb+Zn resource of 1.5 Mt with grades from 1.72% to 10% Pb and Zn. The main host rocks are calcite and/or marl cemented breccias that are strictly limited within the Permian Limestone. Geological mapping and drilling revealed several horizontal breccia belts under the surface. Microtextural observation results, along with previously published data reveal a close spatial and temporal relationship among the marl- and calcite-cemented breccias and the Miocene muddy-limestone and mudstone. Such relationship suggests that the breccias were formed by dissolution and collapse of paleo-caves during the Miocene sedimentation. A temporal link between sedimentation, dissolution, collapse and mineralization processes can be built.