Representative gas chromatographs for the aliphatic hydrocarbon fraction (A) Sample 15/906 shows a clear predominance of medium-chain n-alkanes (n-C₁₂–n-C₂₀) with almost no longer chain molecules. (B) Sample 15/899 illustrates a predominance of medium-chain n-alkanes over abundant long-chain n-alkanes (n-C₂₁–n-C₃₅). (C) Partial m/z 191 mass fragmentograms showing hopane distributions for sample 15/890. (D) Partial m/z 217 mass fragmentograms showing sterane distributions for sample 15/872. Peak identifications are provided on Tab. 2.