Detrital chromian spinels from Miocene and Holocene sediments of northern Iraq: provenance implications

The study integrates mineralogical and chemical characteristics of the chromian spinels from northern Iraq using standard petrographic and scanning microscope techniques as well as electron microprobe analyses in order to better understand their provenance, and the implications thereof. Detrital chromian spinels are found as one of the predominant accessory heavy minerals within fluviatile Miocene and Holocene sediments. In addition, such spinels are also present in the Palaeogene-Neogene and Cretaceous alluvial, deltaic and turbiditic sandstones. The results indicate that most of the chromian spinels have interrelated ranges of Cr/(Cr+Al) at rather low contents of Fe and Ti suggesting that the sandstones which host the chromian spinels were derived from a source area dominated by ultramafic rocks. Mineralogical and chemical data suggest that Alpine-type peridotites were the main source rocks for the studied chromian spinels. All available evidence supports the idea that the sandstones originated from the ophiolite-radiolarite belt of the Taurus Range in northeastern Turkey, as well as from recycling of the uplifted Cretaceous strata of northern Iraq.