Quaternary volcanism in the Alaska Peninsula and Wrangell Mountains, Alaska
The numerous Quaternary volcanoes of the Alaska Peninsula, Cook Inlet area, and the Wrangell Mountains result from underthrusting of the Pacific Plate, or material coupled to the Pacific Plate, beneath the continental crust of North America. These volcanic centers are among the most prominent physiographic landforms in southern Alaska. They include some of the highest (>5,000 m), largest (>1,000 km3), and most explosive (five Holocene eruptions with bulk volumes >50 km3) volcanoes found along the entire circum-Pacific margin.
Edifices of the major Quaternary volcanoes dominate the Alaska Peninsula and Cook Inlet region (Fig. 1); numerous peaks rise 1,800 to 2,500 m above sea level. These volcanic centers, along with those of adjoining Unimak Island, constitute the eastern half of the Aleutian volcanic arc. This classic arc-trench system, equally divided between continental and oceanic segments, extends 2,600 km across the North Pacific. Separated from the northeast end of the Aleutian arc by 400 km is the subductionrelated Wrangell volcanic field of Miocene to Holocene age, which underlies >10,000 km2 of the Wrangell Mountains of south-central Alaska (Fig. 1).
Regional geologic mapping and topical volcanological studies since the early 1970s have resulted in an expanded understanding of the physical volcanology of the eastern Aleutian arc and Wrangell Mountains, including such parameters as size, stratigraphy, eruptive history, spacing, and geologic setting of the volcanic centers. Several volcanoes have now been mapped and studied in sufficient detail to clarify the physical and chemical processes associated with volcanic activity in this part of the circum-Pacific.
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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.