Dolomite Textures in the Upper Part of Jeribe Formation of Sherikh Ibrahim Area, Northwest Iraq

The Jeribe Formation of Sheikh- Ibrahim area is divided into two parts of variable bedding characters. The lower bedded part comprises carbonated beds of chalky, massive and biogenic limestone. The massive upper part is constituted of hard limestone and dolomitic limestone associated with fringing dolomite breccia. The massive limestone is dominated by blue- green algal buildup, which has been highly dolomitized. Petrographic examination of dolomite in the upper part revealed the following textures: aphanotopic, limpid and mosaic dolomite textures. The inference gained from petrographic evidence point to dolomitization by the mixing zone model.