Nannobiostratigraphy of the Lower Part of Shiranish Formation, Sinjar Anticline, NW Iraq

Abstract

Fifteen samples from the lower part of Shiranish Formation, Sinjar anticline, northwest Iraq, are investigated in order to identify calcareous nannofossils species of which twelve species are recorded as follow; one species of holococcoliths, seven are heterococcoliths and four are nannolith. On the basis of the above assemblages two biozones are proposed from oldest (at bottom) to youngest (at top): 2Tranolithus phacelosus Interval Zone(Part) (CC23) 1Lithraphidites praequadratus Partial Zone(Part) (CC22) The above biozones are correlated with other calcareous nannofossils biozones from regional view led to conclude that the section is late Campanian in age. ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ ــــــــــــــــــــــ لا ةيقابطلا ةيسمكلا ونانلا تا رجحتمل ةيتايح ل ءزجم يمفسلا نم شنا رش نيوكت ، راجنس ةيط قا رعلا برغ لامش ،ةبدحملا ع رم ينا ردبلا دمحا مومع مسق ضرلأا مومعلا ةيمك لصوملا ةعماج صخمملا مح تسارد جرومو رشع تسمخ ل ءزجل يلفسلا شوارش هيوكح هم .قارعلا برغ لامش ،راجىس تيط ، صيخشخل وواىلا ثارجحخم هم عوورشع اىثا تيسلكلا جلجس يخلاو ؛يلي امك دحاو عون ( ثيلوكوكولوه ) ةعبسو عاونأ ( كوكورتيه ثيلو ) و ةعبرأ عاونأ ( ثيلونان ) تا رجحتملا عيماجم ىمع دامتعلاابو ، هلاعأ نيقاطن حا رتقا مت ىلا مدقلاا نم امهو نييتايح ثدحلأا : Omar Ahmed Al-Badrani 2 2Tranolithus phacelosus Interval Zone(Part) (CC23) 1Lithraphidites praequadratus Partial Zone(Part) (CC22) قاطىلا ةاٌاضم مح عم يلاعا هي ًقطوا ايميلقا تيسلكلا وواىلا ثارجحخم عطقملا رمع ناب هيبح ثيح نايوابماكلا وٌ سورذملا رخأخملا . ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ ــــــــــــــــــــــ INTRODUCTION The Shiranish Formation was first described by (Henson, 1940 in Bellen et al., 1959) from the High Folded Zone of North of Iraq, near the village of Shiranish Islam, Northeast of Zakho. It is belongs to the most widespread units of the Upper CampanianMaastrichtian cycle in North Iraq. The studied section exposed at the core of Sinjar anticline, northwest Iraq, which belongs to the Foothill Zone of the Unstable Shelf of the Nubio-Arabian platform (Buday and Jassim, 1987). The present study deals with the exposed stratigraphic successions (15 samples of Shiranish Formation), limited between 36o22'45'' N, 41o41'25'' E and 36o22'54N, 41o41'11'' (Fig.1), consists of well beded blue marly limestone with two bed of conglomerate beds (10-15 cm.) in the upper part of studied section. Systematic Paleontology The describtion of calcareous nannofossils species based on Young and Bown (1997) as follows :