In the Shushan Basin, we examined the organic matter under transmitted light microscopy for spore coloration index (SCI) and kerogen type assessment. We used this index to estimate tentative values of the Thermal Alteration Index (TAI) and the Vitrinite Reflectance (Ro) that are equivalent to these SCI values on available standard color charts. Based on that, we inferred the degree of the thermal maturity of the investigated Early (to earliest Late) Cretaceous rock units. We confirmed their previously described high potential as sources of hydrocarbons. However, the Alam El-Bueib, Alamein, Dahab, Kharita, and Bahariya formations contain abundant AOM, frequent opaque phytoclasts, and common non-opaques, indicating oil- and gas-prone kerogen types II and III and reflect mature to overmature hydrocarbon generation potentiality.