Definition of Foraminiferal Zones in the Famennian Stage (upper Devonian) of Tajikistan

Abstract

AbstractSeven foraminiferal zones [Parathurammina dagmarae–Saltovskajina scitula–Neoarchaesphaera, Septaglomospiranella primaeva, Quasiendothyra (Eoquasiendothyra) bella, Q. (Eoendothyra) communis, Q. (E.) regularis, Q. (Q.) kobeitusana–Endoglomospiranella imminuta, and Q. (Q.) konensis–End. Nigra] have been identified from Famennian Stage carbonate sections in Tajikistan and compared to foraminiferal sequences from the Franco-Belgian Basin, the Russian part of the Eastern European Platform, the Ural Mountains (Russia), and Kyrgyzstan. The lower Famennian boundary is marked by the rapid extinction of all Frasnian Stage multicameral forms, which are replaced by a complex of single-chambered foraminifers of the P. dagmarae–S. scitula–Neoarchaesphaera Zone. This boundary practically coincides with the base of the middle Palmatolepis triangularis conodont zone. The upper Famennian boundary is recognized by the sharp change from endothyroid foraminifers of the Quasiendothyra konensis–Endoglomospiranella nigra Zone to a complex of simple mono- and bilocular forms of the Carboniferous Bisphaera malevkensis–Earlandia minima Zone. This boundary in the most intensely studied section at Shishkat is located 16 cm below the boundary of the Siphonodella praesulcata and S. sulcata conodont zones.