Yukon Flats Basin Tectono-Sedimentary Element, East-Central Alaska

Abstract

Abstract Yukon Flats is a vast and remote lowland that straddles the Arctic Circle, and is located along the Yukon River in east-central Alaska. Seismic reflection and gravity data indicate that low-density sedimentary strata beneath Yukon Flats are as thick as 8 km and are underlain by Jurassic–Devonian oceanic rocks of the Angayucham–Tozitna terrane. On the basis of shallow core-hole penetrations and by analogy with nearby outcrops, the low-density strata are thought to consist of fluvial and lacustrine deposits of Neogene, Paleogene and, possibly, Late Cretaceous age. No deep petroleum exploration wells have been drilled in Yukon Flats, but a coalbed methane test reached a total depth of nearly 700 m and found small amounts of microbial methane. Geochemical data from outcrops and shallow core holes suggest that potential source rocks include non-marine coal, mudstone and shale, whereas potential reservoirs include non-marine sandstone and conglomerate. Numerous potential structural and stratigraphic traps are evident on seismic profiles. The United States Geological Survey estimates that undiscovered, technically recoverable, oil resources in the Yukon Flats Basin Tectono-Sedimentary Element range from 0 to almost 600 MMbo, and that undiscovered, technically recoverable, gas resources range from 0 to almost 15 Tcf.