Sedimentary Environments and Age Determination of the Chia Gara Formation, Northern Iraq

The rock successions of the Chia Gara Formation were studied at two surface sections (Barsarin and Rania) from North-Eastern Iraq. detailed sedimentological study reveals that formation consists basically thin-bedded black limestone, dolomitic marly bituminous shales, Ammonitic limestone. petrography results showed various petrographic components as Ammonites, calcispheres, radiolarian, silicate sponges in addition to groundmass micrite. Ammonite taxa are examined upper part find species, which seven species have been identified. One biozone is postulated based on above assemblages, order age: Berriasella Jacobi, a regional perspective, this was connected with other leading conclusion age Early Cretaceous age. facies analysis demonstrates succession mainly three microfacies. main microfacies include lime mudstone, wackestone, packstone. At same time, lithofacies comprise limestones shales. overall characteristics these show deposited different environments; (1) Lower Upper bathyal (2) Middle bathyal, (3) outer shelf environment.