Foraminiferal Biostratigraphy and Paleoenvironment Interpretation of the Paleocene to Eocene Patala and Nammal Formations from Khairabad-East, Western Salt Range, Pakistan

Abstract

   A shaly and marly sequence of Patala and Nammal formations’ (Paleogene) in the Khairabad East section (Western Salt Range) bears rich planktonic foraminiferal assemblages. The analysis of 24 samples collected at varying intervals revealed four biozones from Late Paleocene to Early Eocene age. The Patala Formation ranges from the Late Paleocene P6 zone to Early Eocene P8b zone whereas the Nammal Formation extends from P8b zone close or up to the end of the Early Eocene P9 zone. Qualitative and quantitative analysis of planktonic and benthic foraminifers suggest a deposition in open sea fully marine environments and reflect a shifting tendency from upper slope to outer shelf environments for the Patala Formation whereas the Nammal Formation is indicative of middle to outer shelf environments. The zonal scheme for planktonic Foraminifera is applied after Blow (1979).