Calcareous nannofossil stratigraphy of the upper cretaceous-lower paleocene sequence from the chinarok section, Sulaimaniah area, Kurdistan Region, ne Iraq

Abstract EN

The Cretaceous/ Paleogene boundary in the Kurdistan region of Iraq is still under debate.

Most studies consider the Danian sediments to be mostly missing.

We examined the boundary succession of the Chinarok section in the Sulaimaniyah area of the Kurdistan Region to examine calcareous nannofossil assemblages as well as the biostratigraphy of the boundary.

The rock strata in the study section are characterized by alternations of organic shale, marlstone, siltstone, fine- grained sandstone, and organic limestone interlayer within the Tanjero Formation (upper Maastrichtian) and the overlying Kolosh Formation (Paleocene – Lower Eocene).

The study shows that deposition across the boundary is continuous with no break in sedimentation.

The boundary is biostratigraphically delineated by the first occurrences of Biantholithus sparsus, Cruciplacolithus spp.

and Coccolithus pelagicus plus an acme of Thoracosphaera operculata of biozone NP1 that indicate no hiatus; there is reworking of the Cretaceous taxa all above the Cretaceous/ Paleogene boundary into zones NP1 and NP2