Organic content source beds

Table II shows the results obtained by extracting several Uinta Basin, Utah outcrops with successive organic solvents. All outcrop samples are fairly low in sulfur, most are quite high in nitrogen, and all have low ratios of vanadium to nickel. Only the Raven Ridge sample, which was collected in a creek bed, has a very large fraction of organic material that is not soluble in heptane Benzene-methanol (1 1) and pyridine did not extract much material from any of these samples, so analytical data from these materials are not included in the table. The asphaltenes extracted from P. R. Spring and Southeast Asphalt Ridge tar sands are quite rich in nickel (5/jtmol/g), and nickel porphyrins are found in the heptane-soluble fractions of these tar sands as well as is the heptane-soluble fraction of Whiterocks tar sands. Crudes derived from nonmarine sources are usually much higher in nickel content than in vanadium content, and the Uinta Basin tar sands deposits are all of lacrustine origin and are of tertiary age.

The tectonic regime was characterized by constant subsidence of the basin with few phases of uplift. This led to the deposition of thick sequences of argillaceous rocks with a notable content of organic matter, which could be considered as potential source rocks, and intercalated with them sandy beds were deposited as the eventual reservoirs. 

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