Geology of the southern Alaska margin
Published:January 01, 1994
This chapter summarizes the tectonic setting, geology, and tectonic evolution of the southern Alaska margin south of the Border Ranges fault system, which extends 2100 km from the Sanak Islands on the west to Chatham Strait on the east and seaward to the base of the continental slope (Fig. 1). Mesozoic and Cenozoic rocks that make up the southern Alaska continental margin record a complex history of subductionrelated underplating, offscraping, and metamorphism, as well as transform-related large-scale strike-slip displacements. The region discussed in this chapter has an area of about 328,000 km2, of which almost 30% is onshore. The land area includes parts or all of 26 1:250,000 scale quadrangles.
The mainland along the northern Gulf of Alaska margin consists of alluvium- and glacier-covered coastal lowlands, 0 to 40 km wide, backed by a belt as wide as 40 km of rugged foothills that rise to elevations of about 2000 m (Wahrhaftig, this volume). The foothills are bordered to the north by the exceedingly rugged Kenai, Chugach, and Saint Elias mountains. Average summit elevations are over 2000 m, and numerous peaks are over 5000 m; the highest peaks are Mt. Saint Elias in Alaska (5488 m) and nearby Mt Logan (5745 m) in Canada. All major drainages in the coastal mountains are occupied by glaciers except for the Alsek River, which drains across the Saint Elias Mountains from Canada, and the Copper River, which drains across the Chugach Mountains from the interior of Alaska. The Kodiak Islands group, the islands
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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.