Petrography and geochemistry of Doroud Formation sandstones in the Zal section, Eastern Azarbaijan: implication on provenance, tectonic setting and paleoweathering

In this study, a combination of petrographic and major element geochemistry of siliciclastic deposits of Lower Permian Doroud Formation in the Zal section in south of Jolfa has been used to investigate the provenance, tectonic setting and paleo-weathering. The thickness of Doroud Formation in Zal section is 112 m consisting of micro conglomerate, red sandstone and shale. Thirteen samples of sorted and medium grained sandstones were examined by point-counting method and 6 samples were examined for determination of their major elements by X-ray fluorescence (XRF) method. The studied samples are frequently sublithic-arenite in composition. The study of the amount and type of monocrystalline and polycrystalline quartz and using of discrimination function, indicate that the parent rocks of these deposits are predominantly metamorphic, felsic igneous rocks as well as sedimentary recycled. The presence of chert in petrographic studies has also confirmed the effect of sedimentary recycling from older formations. Petrographic and geochemical studies also indicate the cratonic origin and tectonic setting of the passive continental margin at the time of sediment deposition of the Doroud Formation. Determination of chemical index of alteration (CIA) indicates intense weathering and humid climate in the provenance area, which is consistent with the paleogeography of the Iran in Permian. It seems that factors such as the a long-distance transport on the Arabian Craton, the recycling of older formations and also the humid climate at the time of the deposition of the Doroud Formation, together, have played significant role at the relatively high maturity of this sandstones.