زيست چينه نگاري سازند ايلام در برش الگو و چاه شماره 1 ماله كوه (جنوب شرق ايلام)

Biostratigraphy of the Ilam Formation in the Type Section and Maleh-Kuh Well No. 1 (SE of Ilam city)

A total of 329 samples from the Ilam Formation of the type section and Male-kuh well no. 1 were paleontologicaly investigated to revise the biostratigraphical zonation and determine the paleodepth of this formation. 11 genera and 16 species of planktonic foraminifera and oligosteginids were recorded, which permit the recognition of 3 biostratigraphic zones: Zone 1 (Dicarinella asymetrica zone) suggests Late Santonian. Zone 2 (Globotruncanita elevate zone) confirms Early Campanian. Zone 3 (Globotruncana ventricosa zone) indicates Middle Campanian. Study of morphotype groups of planktonic foraminifera shows that deposition of the Ilam Formation mostly took place in a relatively deep marine condition (more than 100 m).