The origin of kaloutaks sediments in old delta of Hirmand River

Kaloutaks are a geomorphological forms of arid and semi-arid regions around the world. These features are extensive and varied in Iran, resulting from the erosion of fluvial and lake sediments of the Quaternary. Kaloutaks are mostly extended over the Eastern and Southeastern Iran and have unique features. Meanwhile, the kaloutaks in the playa of Sistan Hamun are considerably extended.  The studied area includes part of the kaloutaks in this region.  The main objective of this study was to examine and find the origin of sediments deposited in the old delta of Hirmand River, the main area for the extension of kaloutaks.  To this end, five sediment samples were specifically taken from the area and examined using XRD and XRF laboratory analysis methods.  Results showed that sediments such as quartz, aluminum, calcium, and other evaporates have the highest percentage in kaloutaks.  Moreover, based on the elements obtained from the tests and examining the geographical maps of Iran and Afghanistan, it can be concluded that these sediments have both an internal and external origin. Eroded and sedimented formations of flysch in the Eastern Iran confirm the internal origin of sediments, and the presence of quartz, aluminum, calcite, dolomite, muscovite, albite, and other minerals indicate the external origin of these sediments, transferred by Hirmand River and sedimented in the playa of the Hamun. Based on results, the sediments of the old delta of Hirmand River have provided the best condition for the erosion and formation of kaloutaks in this region due to pedological features and climatic factors.