[en] Coal beds, hydrocarbon source rocks, and natural oil seeps represent potentially significant sources of hydrocarbons contamination of marine sediments in the northern Gulf of Alaska. Intensive studies of several supposedly diagnostic polycyclic aromatic (PAH) and aliphatic hydrocarbon compounds have been conducted to solve the controversy of whether the hydrocarbons come from natural or anthropogenic sources. These hydrocarbons could be associated with a refractory matrix not biologically available, as strongly suggested by the n-alkane profile characteristic of the marine sediments. There are similarities between the unresolved complex mixture (UCM) profile of the marine sediments and those of eroding coals and source rocks. However, there were differences with the UCM of seep oils entering the Gulf of Alaska. The seep-oils possess low concentrations of n-alkanes due to biodegradation before entering the Gulf of Alaska, and have large UCM and PAH concentrations. Additional strong constraints are placed on hydrocarbon contributions from natural sources to the marine sediments of the northern portion of the Gulf of Alaska as a result of inclusion of n-alkane and UCM results into hydrocarbon source allocation models. The authors indicated that seep-oils are unlikely to be significant contributors. 19 refs., 1 tab., 6 figs