Hydrothermal polycyclic aromatic hydrocarbons in marine and lagoon sediments at the intersection between Tjörnes Fracture Zone and recent rift zone (Skjálfandi and Öxarfjörður bays), Iceland

Polycyclic aromatic hydrocarbons (PAHs) in marine and lagoon sediments, and thermal waters were studied in the northern part of the Icelandic recent rift zone and Tjörnes Fracture Zone. All samples analyzed represent slightly altered clastic deposits and hot water discharging from springs and wells. Data obtained show that hydrocarbons are associated mainly with hydrothermal minerals and deep hot thermal ground waters, suggesting that PAH distribution is closely related to the dynamics of hydrothermal environment. Deep emanation of PAHs in present day gas emissions was studied with diatomite absorbent traps. Traps were left exposed at Skógar and Skógalón localities (recent lagoon sediments, Öxarfjörður geothermal field) for 15 and 30 days. Content and distribution of PAHs associations in surface sediments can be used as indicators of hydrocarbon migration and possible zones of hydrocarbon accumulation in land and marine sedimentary basins in active and ancient rift zones of Iceland.