Diagenesis and burial history of nonmarine Upper Cretaceous rocks in the central Uinta Basin, Utah

Rocks of the Upper Cretaceous nonmarine undifferentiated Tuscher and Farrer Formations yield thermogenic gas and some oil from interbedded carbonaceous shales and coal beds. They are interbedded with low-permeability sandstones and formed in a complex fluvial system in the Western Interior foreland basin. Gas-prone source rocks are within the zone of catagenesis, and active hydrocarbon generation probably began about 30 Ma, following deposition of about 9,000 ft of Tertiary sediments during basin subsidence. The similarity between past and present-day geothermal gradients (1.6/degrees/F/100 ft) in the Wilkin Ridge well suggests that heat flow through the central part of the Uinta Basin has been relatively uniform from the Late Cretaceous to the present.