Source and depositional controls on heavy metal distribution in marine sediments of the Gulf of İskenderun, Eastern Mediterranean

The concentrations of major (Al, Mg, Fe, and Mn) and trace (Zn, Cr, Ni, Co, Cu, and Pb) elements as well as carbonate, organic carbon, and grain size distributions have been determined in surface sediments collected at 73 stations from the Gulf of İskenderun. The shelf sediments of the Gulf of İskenderun are largely muds but sediments with higher contents of sand and gravel also occur due to the presence of high biogenic CaCO 3 contents (up to 80%) in the samples. The abundance and regional distributions of elements in the surface sediments of the Gulf are largely controlled by differences in grain size and in the level of dilution by skeletal/shell remains, and by the variation in composition of source materials. Mg, Ni, Cr, Co, and to a lesser extent Zn and Pb, are significantly enriched relative to their average crustal abundances. These metal enrichments are found especially in the eastern part along the SW-NE-trending areas of the Gulf and are mostly consistent with the chemical and mineralogical compositions of the major basic and ultrabasic source rocks present on the adjacent coast and hinterland. There is strong evidence that suggest that aluminosilicates, Fe and Mn compounds (possibly oxyhydroxides), and organic matter act as the most effective carriers for transfer of available metals (Zn, Cr, Ni, Co, and Cu) to the sediments.