Biostratigraphy of Devonian-Carboniferous boundary in Tuyeh-Darvar section, north of Iran

Abstract

Devonian-Carboniferous boundary is not clear in the Eastern Alborz Mountains. In the current study Tuyeh-Darvar section with about 170 m, thickness is selected. In this investigation, the primary goal is revision of Devonian/Carboniferous Boundary (known as DCB) and the other goal is the redefinition of the DCB as a famous necessity (based on ICS program in 2008 for defining the boundary and to find a new GSSP). According to Conodont data from acid-leaching 53 carbonate samples(by acid acetic) that obtained from Late Devonian and Early Carboniferous deposits in this section, and based on standard conodont Zonation 6 Zone are recognized; 1. Bi. ultimus/or Si. praesulcata Zone, 2. Pr. kockeli /or Si. sulcata Zone, 3. Si. duplicata to Si. sandbergi bio interval, 4. Si. crenulata Zone, 5. Gnathodus-P. inornatus Zone, and 6. Ps. multistriatus Zone. Considering to the Conodont Zones above mentioned, Conodont faunas and other evidences, in the Tuyeh-Darvare section the DCB, is located within cream to grey silt stone beds, which are lies between K6 limestone and K8 dark carbonate beds (about 7.10 m above the base of recent studied section). © 2020 Islamic Azad University.