Biostratigraphy of Upper Valanginian - Upper Aptian Balambo Formation Near Barsarin Village in Rawanduz Area, Northeastern Iraq

ABSTRACT The biostratigraphy of Balambo Formation has been investigated within a well-exposed section at the northeastern limb of Zozik anticline, near Barsarin Village, northeastern Iraq. The studied section consists mainly of marl, marly limestone and limestone. These rocks yielded moderately diversified planktonic foraminiferal fauna and radiolarian skeletons, in addition to some benthonic foraminifera and bioclast. The study is focusing on planktonic foraminiferal taxa, which are classified to ten species belonging to three genera. the stratigraphic distribution of the recorded species permits the recognition of five well defined biozones. These are in descending order: . Globigerinelloides algeriana Taxon range Zone. (part) . Globigerinelloides ferreolensis Interval Zone. . Globigerinelloides blowi Interval Zone. . Hedbergella sigali Interval Zone. . Globuligerina hoterivica Interval Zone. The planktonic foraminiferal biozones are correlated with other zonal schemes. They are considered to be extending from Late Valanginian to Late Aptian age.