This study examines the geochemical processes influencing major and trace element distribution in Erg of Tabas barchan sands, focusing on aeolian sorting and chemical weathering. X-ray fluorescence (XRF) data show systematic variations in SiO2, Fe2O3, TiO2, and Al2O3 across the Crest, Lee side, and Stoss side, while previous references to carbonate oxides have been removed to avoid misinterpretation due to pre-treatment of samples. SiO2 enrichment in the Lee side results from quartz overgrowth and fine-grained phase removal, while its depletion in the Crest reflects heavy mineral accumulation (e.g., magnetite, ilmenite) due to gravitational-aeolian sorting. Fe2O3 and TiO2 increase in the Crest, indicating iron-titanium oxide concentration, while their Lee side depletion stems from grain-surface alteration and selective removal of heavy minerals rather than strong post-depositional chemical weathering. Al2O3 variations highlight sorting and diagenetic effects. Geochemical ratios (Cr/V, Ce/Ni, Th/Sc-Cr/Th) suggest mixed felsic-mafic provenance, with the Crest rich in felsic minerals, the Lee side showing subtle signs of surface alteration, and the Stoss side intermediate composition. SEM reveals coarser, pitted Lee side grains (indicating minor surface weathering) versus smoother Stoss side grains. XPL microscopy shows opaque/heavy mineral enrichment in the Crest (similar to 30 %), moderate levels on the Stoss side, and minimal (similar to 10 %) on the Lee side, reflecting wind-driven sorting. Multivariate analyses (PCA, LDA) achieve 94 % classification accuracy, confirming combined aeolian sorting with limited surface alteration controls. These findings provide a geochemical model for aeolian sediment studies in similar environments.