| Abstrakt: |
The depositional environment of the Tanjero Formation has been studied depending on foraminiferal assemblage and microfacies analysis in the Hujran section, northeast of Erbil City (Iraqi Kurdistan Region). The formation in the studied section consists of 30 m of thin bedded yellowish blue marly limestone interbedded with blue marl in the lower part, whereas the upper part consists of thin yellow limestone and yellowish blue marly limestone interbedded with gray marl, shale, and sand. The foraminifera species are extracted from fourteen samples of friable sediments in the studied section. The result shows that the planktonic and benthonic foraminifera have a high abundance and diversity. Based on the ratio of planktonic/total (planktonic + benthonic) %, the paleodepth of the friable rocks of Tanjero Formation in the Hujran section is mostly upper slope with occasional intervals back to the outer shelf. The petrographic components of 15 thin sections of carbonate rocks of the Tanjero Formation include skeletal grains which are planktonic foraminifera, benthonic foraminifera, calcispheres, echinoid spines, ostracoda, bryozoa, brachiopods, bivalves, and bioclasts. Non-skeletal grains contain only extraclasts of monocrystalline quartz. The main groundmass is composed of micrite with some microspars. Three main microfacies were recognized in the Tanjero carbonates. They are grouped into one basic type of facies association based on their environmental interpretation, which is the deep shelf and lower slope. The proposed depositional environment of the Tanjero Formation is a deep shelf and slope environment depending on field observation, foraminiferal content of friable rocks, and microfacies analysis of carbonate rocks. [ABSTRACT FROM AUTHOR] |
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