Major and rare earth element contents in sedimentary rocks of the Haymana formation, Ankara, Turkey

The study area is located 4 km east of Haymana, Ankara, Turkey. Major and rare earth element (REE) contents in samples collected from siltstone, carbonaceous claystone, and marl of the Haymana formation in the studied region and their distribution with respect to lithology and correlation relations yield important data on the evaluation of forming conditions of basin. Regarding the abundance of elements in various lithologies, the first and second group elements (SiO2, Al2O3, Na2O, TiO2, P2O5 and Fe2O3, K2O, REE) are more abundant in carbonaceous claystone and siltstone than that in marl, indicating that they are of detrital origin and controlled by clays. The abundance of CaO and TOT/C is lesser in siltstone than that in carbonaceous claystone and marl, implying that they are in marine origin. This is also supported by the correlation of elements. Based on REE abundances, lithologies are ranked in the order of claystone > siltstone > marl, which indicates that clays play an important role in REE enrichment. Correlation of REEs with major elements is indicative of detrital source and association with clay minerals. All the samples are represented by slightly negative Ce anomaly and positive Eu anomaly. Negative Ce and positive Eu anomalies are mostly typically of high oxygenated environments. Since negative Ce anomaly restricts oxygen enrichment to some extent, deposition environment might reflect oxic-anoxic conditions