Differentiation of Multi-lithotypes Olistostromal Occurrences Associated with Iron Enrichment and Mineralization Within the Ophiolites of Choman Area, NE Iraq

Abstract

The discovery of multi-lithotypes olistostromes deposits associated with potentially economically viable iron ore mineralizations in the Rayat region of NE Iraq are described in this study. The depositional and differentiation-classification characteristics of multi-lithotypes of olistostromes with distinct depositional and characteristics are reported here through detailed petrographic, mineralogical, and geochemical data, allowing for mineralization mechanisms assessment and associated hydrothermal and alteration processes. Ferruginous conglomerate lithotypes occur below the sandstone olistostromes lithotypes section of the investigated series. Through the ferruginous conglomerate olistostromes (FCO) lithotypes, there is a layer of potentially iron ore containing iron oxide (up to %42.55) and quartz with some minor spinel content. Below FCO, there are the horizons of FOpO and FSO, which are also rich in hematite quartz and calcite with some minor spinel content. A 2m thick transition zone (TZ) separates the poorly mineralized ophiocarbonatic olistostrome (OpCO) from FCO. The multi-lithotypes of olistostrome from bottom to top are serpentinite olistostrome (SO), ophiocarbonatic olistostrome (OpCO), ferruginous serpentinite olistostrome (FSO), ferruginous ophiocarbonatic olistostrome (FOpCO), ferruginous conglomerate olistostrome (FCO), and sandstone olistostrome (SstO). In addition to Fe, the other potential economic important elements include nickel (507 to 5816 mg/kg) and cobalt (47.2 to 328.3 mg/kg). The findings indicate that the Rayat olistostromes, such as SO, FSO, OpCO, FOpCO, FCO, and SstO, and the transition zone (TZ) are originated from a mixture of early hydrothermal alteration of serpentinites. The finding of olistostromes in the Rayat exposes NE Iraq as a potential mineral-rich sector.