Geology of southeastern Alaska
Published:January 01, 1994
Southeastern Alaska, an archipelago also known as the “panhandle” of Alaska, is an approximately 52,000-mi2 area of intensely glaciated and heavily forested mountains that rise abruptly from a complex system of deep fiords and inland marine waterways. This area is underlain by a complex and heterogeneous assemblage of rocks, and is cut by an intricate network of thrust, normal, and strike-slip faults (Buddington and Chapin, 1929; Gehrels and Berg, 1992).
Rocks in the panhandle record a long and complete geologic history beginning in the Proterozoic, representing every Phanerozoic period, and continuing into the Holocene. These rocks are herein subdivided into ten tectonic assemblages (Figs. 1, 2, and 3), five of which are terranes that apparently contain distinct geologic records, and five of which are lithic assemblages that are in depositional, intrusive, or unknown contact with the terranes.
This chapter begins with a summary of the regional geology of southeastern Alaska derived primarily from the compilation of Gehrels and Berg (1992) and from more recent studies by us and many others. Next, we discuss the components and characteristics of each of the primary tectonic assemblages that make up south-eastern Alaska and then discuss constraints and speculations on the relations between the terranes. We then present a general overview of the tectonic evolution of the area.
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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.