Groundwater and soil salinization pose a serious threat to agriculture and water availability in arid regions like the Kabudarahang plain in Iran. Despite previous research, there's still a gap in understanding how hydrogeochemical changes relate to specific geological processes, especially in areas with complex hydrogeology. This study aims to fill this gap by identifying the sources and mechanisms of salinization in the Kabudarahang plain, offering new insights for sustainable water management practices in similar regions. To this end, 27 groundwater samples were meticulously collected and analyzed using an integrative hydrogeochemical approach, encompassing Hierarchical Cluster Analysis (HCA), Principal Component Analysis (PCA), Piper and Durov diagrams, hydrogeochemical modeling, and binary diagrams. Additionally, this study leveraged the Normalized Difference Salinity Index (NDSI) based on Landsat 8 satellite imagery from 1992 to 2021, providing a unique longitudinal perspective on the trend of soil salinization. The HCA delineated three distinct groundwater clusters (C1 to C3), illustrating a salinization gradient from recharge-type waters (Ca-HCO3-) in C1 to brackish-type waters (Na-SO42-) in C3, a transition indicative of profound groundwater chemistry alterations through processes such as rock-water interactions with carbonate and evaporite formations, ion exchange, and mineral dissolution. A noteworthy novelty of this work lies in its hydrogeochemical fingerprinting, which directly associates the observed salinization with the Qom and Miocene Marl formations and gypsum dissolution, especially within cluster C3. This identification not only fills a critical scientific gap by pinpointing specific geological contributors to groundwater salinization but also charts the brackish water's journey as it mixes with C2 and discharges into C1, mapping a clear salinization pathway across the region. Furthermore, PCA results underscore the chemical characterization of clusters, offering granular insights into the evolution of groundwater chemistry. The study's longitudinal analysis of soil salinization, evidenced by a significant increase in NDSI values from 1992 to 2021, highlights the worsening scenario and underscores the pressing need for immediate intervention. This comprehensive investigation, by bridging a critical knowledge gap through its methodological approach and findings, lays a foundational stone for the development of targeted and effective strategies to combat groundwater and soil salinization in the Kabudarahang plain and similar settings globally, thereby ensuring the sustainability of these vital resources.