Petrographical study of sandstone of Injana Formation in Bazian (Northern Iraq)‎ and Zurbatya (Eastern Iraq)‎

Abstract EN

The present study focused on petrography of sandstone in Injana Formation in Sulymaniyah( Northern Iraq) namly ; Bazian (Bz) and the other in Wasit( eastern Iraq) namly Zurbatiya(Zu) .

Twenty samples were selected, nine of which represent Bazian (Bz) samples and eleven samples representing Zurbatiya(Zu) samples in term of petrography study .

The study revealed that monocrystalline quartz represents the major quartz type and its lowest percentage was observed in Bazian (Bz) while the highest percentage was observed in Zurbatiyah (Zu) that related with increasing distance from probably source from north east Iraq because high stability of quartz in the long distance of transportation.

Polycrystalline quartz is a function of grain size and it increase with increasing grain size, therefor, the highest average record in Bazian compared to Samples of Zurbatyah .

These grains (monocrystalline and polycrystalline quartz) showed dominant straight and wavy extinction which resulted from the stress on quartz grains that suggested they derived from plutonic igneous rock or metamorphic rock.

These grains are angular, sub-angular and sub- rounded and these criteria are characteristic of immature sandstone.

Orthoclase and microcline are sub- angular to sub -rounded with a slight difference in percentages were observed in sample of Bazian(Ba) and Zurbatiyah (Zu).

Plagioclase is very angular to subangular.

However, Orthoclase and plagioclase may be derived from plutonic igneous rock or metamorphic rocks .Microcline is commonly found in the plutonic igneous rocks .

The highest average of carbonate rock fragments was record in Zurbatiyah (Zu) in compression with Bazian, , while the highest average of metamorphic and igneous rock fragments was in Bazian (Ba) compared to Zurbatiyah (Zu).

Petrographic classification indicated that the samples of Bazian and Zurbatiyah (Zu) are Calclithite , moreover Litharenite, but the samples of Bazian are Lithic arenite to Calci Lithic arenite, wheareas Zurbatiyah (Zu) are Calci Lithic arenite , This reflects the effect of the increase of carbonate rock fragments in Zurbatiyah (Zu) .

Provenance ,the studied samples indicated that the recycled orogen (Undissected Arc) and Lithic Recycled sediments.