Middle to Late Mississippian and Early Pennsylvanian foraminifers from the Dianzishang section, South China: Constraints on the Visean-Serpukhovian boundary and implications for biostratigraphic correlation across the Paleo-Tethys Ocean

Abstract

A high-resolution, integrative stratigraphic framework is critical for better understanding of the co-evolution of marine biodiversity and paleo-environments during the middle Mississippian to early Pennsylvanian. There are, however, inconsistencies regarding the use of conodonts as index fossils for the stratigraphic correlation of this period, partly due to their facies-dependent occurrence. Foraminifera, widely present in both shallow-water carbonate platforms and deep-water slope sequences, offer a more globally applicable tool as auxiliary index fossil. In this study, we present a high-resolution foraminiferal biostratigraphy from the Dianzishang carbonate slope succession in the South China Block. The foraminifers can be identified into four zones: the Paraarchaediscus koktjubensis Zone, Bradyina modica Zone, Globivalvulina moderata Zone, and Postmonotaxinoides Zone, which are correlated with zonations of Iran, the East Europe Platform, and West Europe. The combined foraminiferal and conodont data in the Dianzishang section suggest the FOD of Lochriea ziegleri here is likely younger than the base of the Serpukhovian and the presence of a stratigraphic hiatus around the Visean-Serpukhovian boundary.