Fig. 6

Thermal maturity parameters of C₂₇ steranes for Totalp samples. The classification is from Peters et al. 2005a. The brown shaded area represents the range of complete isomerization for the 20S/(20S + 20R) ααα C₂₇ steranes (ca. 55%) and αββ/(ααα + αββ) C₂₇ steranes (ca. 68%)