Aeolian-Fluvial Interactions in Sandy Sediments of Northeastern Iran: Insights from Quartz Grain Microtextures and Particle Size Distribution.

Document Type : Research Paper

Authors

Department of Soil Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran.

Abstract

This study characterized the particle size distribution and surface microtexture of quartz in sandy sediments in southern Sabzevar to identify the nature of these sediments and the processes affecting their accumulation. Thirty samples were collected from 0 to 30 cm at ~1 km intervals along a transect in three geomorphic surfaces: the Kal-e Shur floodplain (FP), the dune field area (DF), and the distal part of the alluvial fan (DA). Particle size analysis revealed bimodal distributions in FP and DA, with modes in fine sand and very coarse silt, indicating mixed aeolian and fluvial sources. In contrast, the DF surface exhibited a unimodal distribution dominated in fine sand, consistent with aeolian processes. Mean grain size (Mz) averaged 4.1 (FP), 3.05 (DF), and 3.61 phi (DA), and sediments were poorly to very poorly sorted across all surfaces. SEM microtextural analysis of quartz grains showed V-shaped percussion marks, conchoidal fractures, and dissolution features. These textures, combined with grain mgorphology (angular to sub-rounded in FP and DA; rounded to sub-rounded in DF), independently support the interpretation of aeolian dominance in the DF and mixed aeolian-fluvial processes in FP and DA. The integration of particle size distribution, quartz microtexture, and geomorphic context effectively discriminates sedimentary processes in this transitional arid landscape.

Keywords

Desert
Volume 31, Issue 1
June 2026
Pages 104-120

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