Document Type : Research Paper

Authors

• samira Zandifar ¹
• Adeleh Jamalian ²
• Farhad Khaksarian ³
• Hamidreza Abbasi ⁴
• Mohammadreza Forudi Jahromi ⁵

¹ Assistant professor, Desert Research Division, Research Institute of Forests and Rangeland, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran

² Assistant professor, Department of Geology, Faculty of earth Siences, Shahid Beheshti University, Tehran, Iran

³ Researcher, Desert Research Division, Research Institute of Forests and Rangeland, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran

⁴ Assistant professor, Desert Research Division, Research Institute of Forests and Rangeland, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran.

⁵ Assistant professor, Department of Civil Engineering, Dashtestan Branch, Islamic Azad University, Dashtestan, Iran

Abstract

Background and Objectives
Geochemical analyses provide valuable insights into sediment origin, transport mechanisms, weathering processes, sedimentary environments, and tectonic conditions. Identifying the sources of wind deposits and lake sediments is crucial for reconstructing environmental disturbances, assessing dust storm frequency, and understanding long-term landscape evolution. This study investigates the geochemical composition, sediment dynamics, and provenance of wind deposits in the Hamoun Sistan wetland, southeastern Iran, through geochemical analysis.
Methodology
A total of 20 surface sediment samples (0–30 cm depth) were collected based on geomorphological units and topographic maps. Samples were pulverized to 64 µm for analysis. Major oxide percentages and trace element concentrations were determined using a Philips PW2400 XRF (Rh-tube, accuracy: 0.01 wt%) and ICP-MS at the Binaloud Mines Laboratory (Tehran University Science and Technology Park). Data were normalized against the upper continental crust for comparison. Samples S1–S7 were collected from the southern basin, while S8–S20 were from the northern basin. The Ni/Sr ratio cumulative distribution diagram was used for classification, and multivariate clustering was performed using multi-resolution graph-based clustering (MRGC), an unsupervised method suitable for spatially undefined datasets.
Results
Sediments in the southern basin exhibit higher concentrations of detrital particles (quartz, fine-grained mica, and carbonates), supported by a strong correlation (R² = 0.77) between SiO₂ and Al₂O₃, indicating aluminosilicate dominance. In contrast, northern samples show elevated MgO, CaO, and Na₂O levels, suggesting mafic/ultramafic source rocks, along with high Fe₂O₃ concentrations indicative of iron-bearing minerals (e.g., biotite, amphibole).
Northern sediments, rich in quartz, feldspar, and mica, align with intermediate igneous rock compositions, implying an igneous origin. Southern samples, dominated by quartz and feldspar, reflect sedimentary recycling and higher maturity (classified as arenites), whereas northern sediments are greywackes.
Trace element analysis reveals greater enrichment of Rb, Ba, and Sr in northern samples, while high-field-strength elements (Th, U, Hf, Zr) remain immobile. Lower Ni, Cr, and V concentrations in southern samples indicate minimal mafic influence, supported by higher LREE/HREE ratios, consistent with felsic-rich sources.
Tectonic discrimination places northern sediments in an active continental margin setting, while southern samples exhibit transitional active-passive margin characteristics.
Conclusion
Geochemical and petrographic analyses reveal distinct sediment provenances for the northern and southern Hamoun wetlands. Northern sediments derive from erosion of eastern Afghan Hamoun Basin rocks (active margin), whereas southern sediments originate from western passive margin sources. These findings highlight the wetland’s complex sedimentological history and provide a basis for future soil erosion and dust storm management.