Biological markers and carbon isotope composition of organic matter in the Upper Cretaceous coals and carbonaceous shale succession (Jiza-Qamar Basin, Yemen): Origin, type and preservation

Based on the analysed biomarker thermal maturity indicators, it may be deduced that the Mukalla coals and carbonaceous shales in the Jiza-Qamar Basin have entered an early-mature to mature stages for hydrocarbon generation. This is also supported by vitrinite reflectance values of 0.63-0.83% Ro indicative that these sediments have reached oil window maturity.