Khurmala Formation (Late Paleocene-Early Eocene) in Halabja area, Kurdistan Region, Iraq

Abstract

The studied section of Khurmala Formation (Late Paleocene-Early Eocene) is located in the Nawar Mountains on the northern part of the entrance of Sirwan River in Darbandikhan Lake. The section is mostly composed of dolomitic limestone, with occasional occurrence of sparsely fossiliferous limestone which are white, light grey and yellowish grey in color. The thickness of this section is almost 73 m and a total of 52 samples were collected at intervals of 0.5-3.0 m according to the lithological changes. Fifty-two thin sections were prepared and analyzed under a binocular microscope. The microfacies distinguished are Boundstone with corals, Bindstone with coralline red algae and corals, Bioclastic grainstone, Bioclastic oolitic grainstone, Bioclastic packstone, and Wackestone. These facies were interpreted to be deposited mainly in the shoal and lagoon of inner ramp environment. Although the studied section is not rich in fossils and most of them were destroyed by diagenesis processes, the following have been identified: Spongites sp., Cymopolia ellongata, Mesophyllum sp., Sporolithon sp., Idalina sinjarica, Quinqueloculina, Cymopolia sp. and Spongites cf. albanensis Lemoine.