Organic carbon chemistry of ODP Hole 151-909C (Table 1)

Organic-rich sediments were recognized in early Miocene strata from the Norwegian-Greenland Sea during ODP Leg 151. Three organic-geochemical subunits were distinguished in Hole 909C using detailed organic-geochemical and microscopic analyses. TOC (up to 3 wt%), HI (up to 200 mg HC/g TOC), and d13Corg values (~24–26 per mil) indicate the predominance of terrestrial type III organic matter in Subunit 3 (~18–16.2 Ma). Biomarker and vitrinite reflectance values (R0 ~0.5%) point to rather fresh immature terrestrial organic matter supplied by river discharge from adjacent vegetated coastal areas. Although the sediments of Subunit 3 have a fair (to good) source rock potential they are insufficiently mature to generate significant amounts of oil or gas. To test if the moderate generation potential and source rock quality of Subunit 3 are applicable to the entire area, the computer software OF-Mod was applied. Several modelling runs testing the most probable depositional scenarios result, even under conservative assumptions, in the formation of good to excellent source rocks towards the basin margins.