ABSTRACT
Tectonic interpretations of Alaska in the past have relied largely on observable structural data. Recent detailed study of known stratigraphic information has led to an alternate picture of Alaskan tectonogenesis. By relating sedimentary facies to tectonic environments a postulated geologic history from the Early Cambrian through Late Cretaceous has been reconstructed. This history indicates that the Alaska area may be composed of two continental (sialic) plates that were once separate. These plates drifted toward each other during the Paleozoic and early Mesozoic, finally impinging and coalescing in Late Jurassic-Early Cretaceous time. Each of the plates involved can be subdivided further into two segments. These segments apparently had somewhat different geologic histories during the formation of the present-day Alaska area.
