Major, Trace, and Rare Earth Elements Geochemistry of the Upper Miocene Injana Formation Sandstone, Northern Iraq: Provenance, Paleoclimate and Palaeoweathering

To determine the provenance, paleoclimate and palaeoweathering of the Upper Miocene sandstones of the Injana Formation, 12 sandstone samples from two sites (Mirawa and Degala) in Erbil Governorate, northern Iraq are investigated. Major, trace, and rare earth elements are measured using X-ray fluorescence (XRF) and inductively coupled plasma-mass spectrometry (ICP-MS). The elemental concentrations and ratios of the studied sandstones indicate their sources from intermediate to mafic igneous rocks. All the chondrite-normalized REEs samples are similar and exhibit a minor enrichment of light rare-earth elements (LREE) in comparison to the heavy rare earth elements (HREE) with a negligible negative europium (Eu) anomaly. The low to moderate values of the plagioclase index of alteration (PIA), chemical index of alteration (CIA), high values of index of compositional variability (ICV > 1), and the A-CN-K plot, all indicate a low to moderate chemically weathered source area. Palaeoclimatic information can be provided using the plot of the SiO2 versus (Al2O3+Na2O + K2O) indicating that the deposition of Injana sandstones has occurred under fluctuated climate between arid to semi-arid.