High resolution biostratigraphic analysis of the danian stage, per fat section, duhok area, kurdistan region, north of Iraq

Abstract

The occurrence of the Danian Stage at Kurdistan Region of Iraq, particularly in the high folded zone, was a debatable subject by many authors. Most of the previous studies believe that it is poorly preserved. This study reviews the Danian sequence at Per Fat of Duhok area using high resolution biostratigraphic analysis of the planktic foraminifera. The Danian stage sequence in the studied locality is represented by the marlstone, shale, and marly limestone rock types of the Aaliji Formation. Occasional iron oxides and microscopic glauconites intervals are characteristics. The thickness of the Danian sequence is about 29.71 m. The sequence is underlined by the Upper Cretaceous Shiranish Formation, and overlies by the green-olive clastic sediments of the Paleocene Kolosh Formation. Biostratigraphic zonation of the identified foraminiferal assemblages shows the occurrence of the four Danian Planktic foraminiferal biozones and three subzones including Guembelitria cretacea partial-range zone (P0); Parvularugoglobigerina eugubina total range zone (Pα); Parasubbotina pseudobulloides partial-range zone (P1); Globanomalina archaeocompressa partial-range subzone (P1a), Subbotina triloculinoides interval subzone (P1b), Globanomalina compressa-Praemurica inconstans interval subzone (P1c); and Praemurica uncinata interval zone (P2). This indicates a complete sequence of the Danian stage is preserved in the Per Fat section of Duhok area.