Mineralogy and Petrography of Fatha gypsum rocks in Zurbatiyah area, eastern Iraq

Abstract

Gypsum rocks of the Fatha Formation in Zurbatiyah area, eastern Iraq were studied in terms of mineralogy and petrography. Mineralogically, X-ray diffractometry results reveal that gypsum rocks are predominantly composed of gypsum minerals with minor amounts of calcite, anhydrite, bassanite and dolomite minerals. Scanning electron microscopy has shown that gypsum rocks have rich inclusions with (Mg) in some samples. Fatha gypsum rocks have higher thickness in the succession of formations with marl, clay and limestone forming multi cyclic deposition. The thickness of Fatha formation in the studied area reaches 525 m. Petrographical and textural analyses reveal the common petrographical texture types of gypsum, alabastrine, satinspar, selenite, porphyroblastic, blocky, and columnar gypsum textures reflect evolutionary alterations in relationships such as crystallization and recrystallization of gypsum rocks. The secondary hydration of anhydrite to gypsum and other alteration changes refer to shallow marine, supra-tidal and continental environments in the Fatha Formation.