Interior Provinces in Alaska: ABSTRACT

Abstract

The U.S. Geological Survey is using a multidisciplinary approach to assess the petroleum potential of the interior provinces of Alaska. Geophysical parameters, petroleum geochemistry, thermal maturation, paleontology, and petrography are some of the disciplines being used to evaluate the basins as well as to compare them geologically with other explored basins. Three types of interior provinces have been tested by exploratory drilling for their petroleum potential: three Tertiary nonmarine basins, two Jurassic and Cretaceous flysch and fold belts, and a Paleozoic thrust belt. Although the presence of hydrocarbons has not yet been demonstrated, the present data base is too limited to make a definitive assessment of hydrocarbon potential. During the 1983-84 field seasons, we acquired new gravity data and collected rock samples in and adjacent to the Yukon flats and the Nenana basins. These basins contain upper Tertiary, primarily nonmarine, sedimentary rock in extensional graben and half-graben complexes that are superimposed across preexisting terrane boundaries. The location and development of the basins result from strike-slip motion along the Tintina and Denali fault systems. Adjacent to the basins and within the fault systems are thick sections of nonmarine lower Tertiary coal-bearing rocks in deformed basin remnants. If these lower Tertiary rocks are present beneath the upper Tertiary fill, their greater depth and advanced maturation could enhance the hydrocarbon generative potential. Gravity modeling suggests th Tertiary fill is at least 3 km thick in the deeper parts of the basins and may be significantly thicker. End_of_Article - Last_Page 667------------