Tephrochronologic correlation of upper Neogene sediments along the Pacific margin, conterminous United States
A. M. Sarna-Wojcicki, K. R. Lajoie, C. E. Meyer, D. P. Adam, H. J. Rieck, 1991. "Tephrochronologic correlation of upper Neogene sediments along the Pacific margin, conterminous United States", Quaternary Nonglacial Geology, Roger B. Morrison
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We summarize results of tephrochronologic studies conducted along the Pacific margin of the conterminous United States during approximately the last 20 years. Tephrochronology, the use of volcanic ash and tuff beds (tephra layers) to correlate and date late Neogene sedimentary and volcanic deposits, has provided numerical age control and relative temporal correlation in many studies of regional geologic mapping, stratigraphy, tectonism, volcanism, and paleoclimate within the Pacific margin of the United States (e.g., Wilcox, 1965; Westgate and others, 1970; Randle and others, 1971; Sarna-Wojcicki, 1971, 1976; Mullineaux, 1974, 1986; Mullineaux and others, 1975; Mehringer and others, 1977, 1984; Crandell and Mullineaux, 1978; Davis, 1978; Porter, 1978, 1981; Izett, 1981; Sarna-Wojcicki and others, 1979, 1984, 1985, 1987). Because individual tephra layers allow precise temporal correlations over great distances, tephrochronologic studies in this region have made it possible to correlate deposits among numerous depositional basins and diverse depositional facies. Furthermore, because deposits of continental and marine environments can be correlated by means of tephra layers, we can compare and equate independently derived provincial and global biostratigraphies that have been developed for the two realms. Correlations of tephra layers also complement or check other dating methods such as biostratigraphy, magneto-stratigraphy, and isotopic ages (Sarna-Wojcicki and others, 1987; also see Sarna-Wojcicki and Davis, this volume).
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Includes 5 topical chapters covering paleoclimates, dating methods, volcanism, tephrochronology, and Pacific margin tephrochronologic correlation, and 15 chapters of regional synthesis covering: the Pacific margin; the Columbia Plateau; the Snake River Plain; the major pluvial lakes of the Great Basin; the Basin and Range in California, Arizona, and New Mexico; the Colorado Plateau; the Southern and Central Rocky Mountains; the Northern and Southern Great Plains, Osage Plains, and Interior Highlands; the Lower Mississippi Valley; the Gulf of Mexico Coastal Plain and Florida; the Appalachian Highlands and Interior Low Plateaus; and the Atlantic Coastal Plain. A large, full-color geologic map of the Quaternary deposits of the Lower Mississippi Valley, in addition to correlation charts, tables, and cross-sections relating to other chapters, is also included.