The Heatherdale Shale and the stratigraphically younger Karinya Shale are transgressive units within the Lower Cambrian of the Karinya Syncline. Black muds of the Heatherdale Shale were deposited in an outer ramp setting of the Stansbury Basin under fluctuating suboxic/anoxic conditions. Interbedded sands at the top of this unit reflect the shallowing of the marine environment prior to the deposition of the Carrickalinga Head Formation. During a later transgression, the Karinya Shale was deposited in the rapidly subsiding Kanmantoo Trough. The Karinya Shale represents a fining-upwards cycle, with pyritic black muds deposited in the upper part of the sequence during maximum sea level. Both formations were deposited during periods of thermal subsidence and relative sea level rise, following episodes of lithospheric extension. A cumulative thickness of 132.5 metres of organic-rich shale (TOC > 0.5%) exists within the Heatherdale Shale at Red Creek, whereas a minimum cumulative thickness of 75 metres of organic-rich shale exists within the Karinya Shale at Frankton. Kerogen studies of samples taken from the Heatherdale Shale and Karinya Shale indicate that kerogens present are of a graphitic nature. The low H/C (less than 0.12) and high C/N (greater than 587) atomic ratios of these kerogens, and their high carbon contents (C > 92% d.a.f.), indicates that thermal alteration during metagenesis of incipient metamorphism has taken place. The H/C atomic ratio of the Heatherdale Shale (H/C < 0.02) indicates that this unit is of a higher metamorphic grade than the Karinya Shale (H/C < 0.12). The carbon isotopic composition of kerogens in the Heatherdale Shale (delta 13C PDB -19.7 to -15.7 per mil) and the Karinya Shale (-25.1 to 20.8 per mil) also suggests that metamorphic alteration of these units has taken place. The Heatherdale Shale at Sedan Quarry contains the highest rank kerogen in the Karinya Syncline. The kerogen compositions of these formations reflect the greater degree of burial of the Heatherdale Shale in comparison to the stratigraphically younger Karinya Shale. Metamorphic grade within the Karinya Syncline is a result of 1) depth of burial, 2) structural complexities, 3) igneous intrusions, and 4) regional metamorphism. Kerogens of the Heatherdale Shale and Karinya Shale were initially of Type II composition, and therefore oil prone. However, the hydrocarbon generating potential of these units has been exhausted, and they are now overmature.