Subsurface sediments from a pockmark area in South-Western Barents Sea have been earlier found to
contain elevated levels of petroleum-related polycyclic aromatic hydrocarbons. This work describes
a comprehensive analysis of various biomarkers, including the highly source-specific hopanes, in a 4.5 m
long gravity core from the same area, together with subsurface sediment samples from other areas in the
region without pockmarks present (“background samples”). A clear difference between the pockmark
gravity core and the background sediment cores was found, both with regard to genesis and the level of
transformation of organic matter. A number of indicator parameters, such as methylphenanthrene index
(MPI-1), point towards a significantly higher maturity of hydrocarbons in the pockmark core throughout
its length as compared to the other sampled locations. Higher contents of microbial hopanoids (hopenes)
may indicate the former presence of petroleum. These findings confirm the hypothesis of a natural
hydrocarbon source in the deeper strata present in the studied location with pockmarks