Megafossil biostratigraphy of some deep test wells, National Petroleum Reserve in Alaska

摘要: Fourteen of the exploration wells drilled on National Petroleum Reserve in Alaska (NPRA) since 1975 yielded significant megafossils, which provide new biostratigraphic information for northern Alaskan subsurface. stratigraphic intervals ranging from possible Late Devonian to Albian (late Early Cretaceous) age are documented. Eight located near Arctic Coast, where many formations pinch out against Barrow High, but five others were into basinal sequences south, Paleozoic and lower Mesozoic strata thicken greatly. By far best documented well is second deepest one, Inigok No. 1, part Umiat basin. Tunalik 1 well, a depth 6198 m (20,335 ft) western NPRA about 50 km southwest Wainwright, apparently penetrated upper Carboniferous immediately above basement. Lisburne structurally complex foothills belt southern NPRA, passed through several thrust slices that late Triassic fossils.