THE SEDIMENTARY IRONSTONE DEPOSITS IN THE WESTERN DESERT OF IRAQ: AN OVERVIEW

Abstract

Two main sedimentary ironstone deposits are investigated in the Western Desert of Iraq; the Ga'ara and the Hussainiyat deposits. The former is found within the fining-upwards successions of the Ga'ara Formation (Permocarboniferous) and the latter within the Clastic Unit of the Hussainiyat Formation (Lower Jurassic). Both deposits are continental, deposited in fluvial systems (meandering rivers represented by channels and floodplain deposits with lakes and marshes, with lateritic characteristics. They are mostly pisolitic-oolitic, concretionary, fragmentary and massive in texture and composed of goethite and hematite in association with kaolinite and quartz. The source rocks are highly weathered igneous, metamorphic and older sedimentary rocks of the Arabian Shield, transported by rivers to the depositional sites. The ironstone resources are limited (~80 m.t.) and the grade is low (<40% Fe2O3) with high contents of kaolinite and quartz impurities. Two open pit mines in the Ga'ara and Hussainiyat deposits have been operating since the early nineties to supply the cement industry in Iraq.