Economic geology of the Mishraq native sulfur deposit, northern Iraq

The Mishraq native sulfur deposit is in northern Iraq about 40 km southeast of Mosul and 315 km north of Baghdad. This deposit is the largest known occurrence of stratiform bioepigenetic sulfur, containing at least 100 million tons of elemental sulfur. It under-lies a 10 km 2 portion of the southeast end of a northwest-trending, doubly plunging anti-cline on the west bank of the Tigris River at its confluence with the Great Zab River. The deposit is in one anticline among many in the folded portion of the Mesopotamian depression and represents part of what may be the largest reserve of elemental sulfur in the world. Small, tight, en echelon folds are superimposed on the southwest limb of the Mishraq anticline with axial trends similar to the main fold (320ø). Faulting is normal and re-verse with dominant northwest and subordinate northeast rends. Mining-induced sub-sidence of 4 to 5 m causes fractures which tend to follow these preexisting directions. The sulfur mineralization is in three main zones of vuggy and bituminous bioepigenetic limestone in the basal Lower Fars Formation of middle Miocene age and marine origin.