Provenance analysis and maturity of the Rayen River sediments in Central Iran: based on geochemical evidence

The purpose of this study is to use the geochemical analysis of recent sediments from the Rayen River (length of about 25 km), located in the Central Iranian zone and Urumieh-Dokhtar Magmatic Belt, to interpret their compositional maturity, chemical weathering, source rocks, and tectonic setting. Geochemical analysis (major and trace elements) of ten sediment samples suggests that mafic and intermediate igneous rocks are the sources of these sediments. Based on discriminant function, binary and ternary diagrams, it is concluded that the tectonic setting of the study area is similar to a continental island arc. The Chemical Index of Alteration (CIA) ranges between 50 and 57, suggesting low-to-moderate chemical weathering that reflects tectonic activity, erosion, and rapid deposition under arid climatic conditions, which gradually increased through time in the source areas. The ICV (Index of Compositional Variability) values show that these sediments have low compositional and mineralogical maturity. It is also shown that the bed load in the Rayen River has a mixed source from undifferentiated volcanic rocks. The data obtained from both petrography and geochemical analysis, which reflect the tectonic and climatic conditions in the study area, can be used as a guide for the interpretation of similar ancient sedimentary records.