PETROLOGY OF THE INJANA FORMATION (UPPER MIOCENE)AT ZAWITA, AMADIYA AND ZAKHO AREA, NORTHERN IRAQ

This study deals with the petrology of Injana Formation (Upper Miocene) at Zawita, Amadia and Zakho areas. The sandstone of Injana Formation is of two typesnamely, litharenite and feldspathiclitharenite. The rock fragments of Injana Formation are mostly sedimentary and hence the sandstones are classified as sedarenite and more specifically chertarenite owing to the predominance of chert rock fragments. The sandstone is mineralogicallysubmature rangingfrom mechanically and chemically stable tounstable. The petrographic studies reveal nearness of source area with arid to semi-arid climate. The source rocks are sedimentary, low- to medium-grade metamorphic and basic volcanic rocks. They are mostly supplied from the rising mountain farther north and east (Taurus and Zagros Ranges) during the Alpine Orogeny induced by the continent-continent collision between Arabia and Eurasia.The mudstone consists of mixture of clay and silt with variable percentages. The major clay minerals are chlorite, kaolinite and mixed-layer illite-smectite. The non-clay minerals are calcite, quartz and subordinate feldspars.