Geology of south-central Alaska
South-central Alaska is defined as the region bounded by the Kuskokwim Mountains to the northwest, the basins north of the Alaska Range to the north, the Canadian border to the east, and the Chugach Mountains to the south (Fig. 1). This region, hereafter called the study area, includes the Alaska Range, the Wrangell, Nutzotin, and Talkeetna mountains, the Copper River and the Susitna basins, the northern flank of the Chugach Mountains, the Aleutian Range, and the Alaska Peninsula. This chapter describes and interprets the bedrock geology of the region, which consists mostly of a collage of Paleozoic and Mesozoic tectonostratigraphic terranes (hereafter referred to as terranes), Mesozoic flysch basin deposits, late Paleozoic and Mesozoic plutonic rocks, and younger late Mesozoic and Cenozoic sedimentary, volcanic, and plutonic rocks. Cited published sources and new data and interpretations of the authors are utilized for the descriptions and interpretations. The terranes, flysch basin deposits, and younger Mesozoic sedimentary, volcanic, and plutonic assemblages are described first in a general northwest to southeast order. Major faults or sutures are described second. Stratigraphic linkages and structural and tectonic relations between terranes are described last. Definitions of the various stratigraphic, structural, and tectonic terms are stated at the end of this introduction.
The three largest terranes in the study area are the Alexander, Peninsular, and Wrangellia terranes (Fig. 2) (Jones and others, 1981, 1984, 1987). Even though many boundaries between the three terranes are commonly faults, important stratigraphic linkages exist. These linkages suggest a common history since the
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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.