H. Richard Lane

Late Visean – early Serpukhovian conodont succession at the Naqing (Nashui) section in Guizhou, South China

This study reports the conodont succession across the Visean–Serpukhovian (V/S) boundary interval at the Naqing section, South China. Continuous centimetre-scale sampling of the relatively deep-water section in recent years has provided new data for a more detailed biostratigraphy of conodonts across the Visean–Serpukhovian boundary. Three conodont zones were described in ascending order: the Gnathodus bilineatus , Lochriea nodosa and Lochriea ziegleri zones. The first appearance datum (FAD) of L. ziegleri has been moved down to 60.1 m above the base of the Naqing section. The correlation of the conodont succession across the Visean–Serpukhovian boundary in the Naqing section with other sections in Eurasia is discussed.

Progress toward Reconciliation of Lower Mississippian Conodont and Foraminiferal Zonations

Calcareous foraminifers and algae and conodonts indicate that the late Osagean Keokuk Limestone near its type section correlates with Visean strata in Belgium. This discovery necessitates shifting the Mamet foraminiferal zonal scheme so that the Keokuk is no older than Zone 10 and possibly as young as Zone 13, rather than corresponding to Zones 8 and 9. The occurrence of the conodonts Eotaphrus burlingtonensis and Polygnathus mehli near the top of the Burlington Limestone in its type area suggests that the Tournaisian-Visean boundary probably corresponds with the Burlington-Keokuk contact.