A comprehensive mineralogical and geochemical assessment of the Early Cretaceous Nubian Formation, comprising the Lower Nubian Sandstone, Varicolored Shale, and Upper Nubian Sandstone, was conducted using samples from well MM1-82 in the Sirte Basin, north-central Libya. Four analytical techniques were employed: X-ray diffraction (XRD), Rock-Eval pyrolysis, gas chromatography (GC), and isotope ratio mass spectrometry (IRMS). Mineralogically, the shale intervals of the Lower Nubian Sandstone consist of argillaceous shale (CM), silica-rich argillaceous shale (CM-1), and mixed argillaceous shale (CM-2), whereas the Varicolored Shale is predominantly argillaceous. The sandstone intervals comprise quartz arenite, lithic sandstone, arkose, and subarkose. Geochemical results indicate poor to fair organic richness, with kerogen types II, II/III, III, and IV. The Lower Nubian Sandstone, Varicolored Shale, and Upper Nubian Sandstone exhibit early mature, immature to early mature, and immature thermal maturity levels, respectively. Indigenous hydrocarbons were detected in all studied samples except those from the Upper Nubian Sandstone. The Lower Nubian Sandstone has fair to good oil-source potential, while the Varicolored Shale ranges from very poor to gas- and/or oil-prone. Despite its immature thermal maturity, the Upper Nubian Sandstone represents the most prospective interval due to its high oil saturation and excellent recoverable oil potential. Shale oil analysis indicates that Lower Nubian Sandstone contains thermally mature oil derived from multiple marine-related source rocks.................... Keywords:................ Mineralogy, Organic Geochemistry, Nubian Formation, Sirte Basin, Libya.