Interior Alaska has historically been considered the onshore geographic area of Alaska between the Brooks Range and the Seward Peninsula on the north and west respectively, and the Alaska Range on the south (Fig. 1). It is an area of more than 600,000 km2 that covers the central one-third of Alaska and has been variously referred to as the “intermontane plateaus” (Wahrhaftig, this volume) and the “central plateaus” (Raisz, 1948). The Yukon River, the largest river in Alaska, approximately bisects the province. The topography of the region is generally subdued. Broad alluviated lowland areas are underlain by Cenozoic nonmarine sedimentary rocks. Extensive areas in the western and southwestern parts of the province are characterized by ridge and valley topography cut in complexly deformed Jurassic and Cretaceous flysch rocks. The Brooks Range and the Alaska Range were extensively glaciated during the Pleistocene; however, only a few very small glaciers were present in the higher mountains of the interior province. Muskeg and tundra at the lower elevations, willow and alder brush in the stream valleys, and spruce and birch forests up to the tree line, at about 750 to 900 m elevation, form a thick cover of vegetation so that bedrock exposures are generally limited to ridge tops above the tree line and river-cut bank exposures.
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The Geology of Alaska
You get a comprehensive overview of the geology, tectonic evolution, and mineral resources of Alaska and adjacent areas of the continental margin. Plates include state-wide maps showing geology, physiography, lithotectonic terranes, metamorphic rocks, igneous rocks, sedimentary basins, isotopic age data, neotectonics, isostatic gravity, magnetics, and metallic mineral deposits. Summaries of bedrock geology and geologic history are given for eleven large regions of Alaska and adjacent offshore areas. Twenty topical chapters synthesize data on metamorphic and igneous rocks; major onshore and offshore sedimentary basins; the paleomagnetics evidence for latitudinal displacements and rotations, glacial history and periglacial phenomena; and the occurrence, evolution, and potential of Alaska's vast resources of petroleum, coal, and metallic minerals. A summary chapter provides an overview and presents a possible model for Alaska's Phanerozoic evolution. The Geology of Alaska is the largest publication produced in the Decade of North American Geology program, a fitting tribute to this magnificent area.