The North China Craton hosts extensive Late Carboniferous karst- type bauxite deposits; however, the mechanisms governing their spatial differentiation and the genetic relationships between bauxite and claystone remain controversial. This study investigates the Nangoucun deposit in the Gongyi area of western Henan Province, integrating multi- scale mineralogical analyses and paleoenvironmental reconstruction to elucidate the metallogenic evolution of these bauxite (clay) deposits. Field investigations reveal a characteristic karst- type bauxite sequence, which consists, from bottom to top, of a ferruginous weathering crust, ferruginous clay rock, and aluminous clay rock/bauxite. Results from X- ray diffraction (XRD) and electron probe microanalysis (EPMA) indicate that the bauxite (clay) deposits are predominantly composed of kaolinite, illite, goethite, hematite, anatase, rutile, and quartz. Stratigraphic variations in alkaline- environment indicators (e.g., illite, diaspore, chlorite) and acidic- environment indicators (e.g., kaolinite) across different layers collectively suggest a complex spatiotemporal evolution involving weathering, transportation, mineralization, and reworking. Notably, diaspore in oolitic bauxite is preserved only as micron- scale oolitic relics, with widespread kaolinization observed throughout mineral assemblages. This layer is also enriched in cubic hematite and weathering- resistant anatase. These features collectively indicate intense supergene weathering and acidic leaching, which drove the selective dissolution of primary aluminum hydroxides and the subsequent transformation of clay minerals. These findings therefore provide critical mineralogical insights into deciphering the multi- stage phase transformation mechanisms of aluminosilicates within paleokarst systems.