Sedimentary characteristics and sequence stratigraphy of the Permian Maokou Formation in the Ganzhai section, Pingtang, Guizhou

According to the sedimentological methods, the present paper deals, in detail, with the sedimentary characteristics and sequence stratigraphy of the Permian Maokou Formation in the Ganzhai section, Pingtang, Guizhou. The rock types of the Maokou Formation mainly consist of sparry-micritic bioclastic limestone, biogenic limestone, micritic limestone, intrasparite, siliceous rocks, nodular limestone and cherty limestone. The fossil types in the Formation comprise ostracods, gastropods, brachiopods, trilobites, algae, echinoderms, fusulinids, corals and crinoids. The lithology and fossils cited above indicate the open carbonate platform sedimentary environment of the Permian Maokou Formation. Three third-order sequences have been distinguished, including PSQ1, PSQ2 and PSQ3, all of which are built up of the transgressive (TST) and highstand (HST) systems tracts. The development of these sequences may be controlled by the sea-level changes. The sequence boundaries P₂q/PSQ1, PSQ1/PSQ2 and PSQ2/PSQ3 represent lithologic-lithofacies transform surfaces. The sequence boundary P₃l/PSQ3 exhibits a tectonic unconformity due to the influence of the Dongwu movement during the latest Maokouan.