Basement geology of the National Petroleum Reserve Alaska (NPRA), Northern Alaska

Open-File Report 2002-127
By: , and 



Gravity, aeromagnetic, seismic, and borehole information enable mapping of crustal basement characteristics within the National Petroleum Reserve Alaska (NPRA). In general, the pre-Mississippian basement of the southern portion of the NPRA is different from that in the north in that it is deeper and thinner, is made up of dense magnetic rocks, is cut by more normal faults, and underlies thicker accumulations of Mississippian to Triassic Ellesmerian sequence sedimentary rocks. Mafic igneous rocks within the basement and locally within the deeper Ellesmerian sequence sedimentary section could explain the observed density and magnetic variations. Because these variations spatially overlap thicker Ellesmerian sequence sediment accumulations, they may have developed, at least in part, during Mississippian to Triassic extension and basin formation. If this period of extension, and postulated mafic magmatism, was accompanied by higher heat flow, then early Ellesmerian sequence clastic sediments may have become mature for hydrocarbon generation (Magoon and Bird, 1988). This could have produced an early petroleum system in the Colville basin.
Publication type Report
Publication Subtype USGS Numbered Series
Title Basement geology of the National Petroleum Reserve Alaska (NPRA), Northern Alaska
Series title Open-File Report
Series number 2002-127
DOI 10.3133/ofr02127
Year Published 2002
Language English
Publisher U.S. Geographical Survey
Description 11 p.
Country United States
State Alaska
Scale 500000
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