Middle and Late Proterozoic stratified rocks of the western U.S. Cordillera, Colorado Plateau, and Basin and Range province
Published:January 01, 1993
Paul Karl Link, Nicholas Christie-Blick, William J. Devlin, Donald P. Elston, Robert J. Horodyski, Marjorie Levy, Julia M. G. Miller, Robert C. Pearson, Anthony Prave, John H. Stewart, Don Winston, Lauren A. Wright, Chester T. Wrucke, 1993. "Middle and Late Proterozoic stratified rocks of the western U.S. Cordillera, Colorado Plateau, and Basin and Range province", Precambrian, John C. Reed, Jr., Marion E. Bickford, R. S. Houston, Paul Karl Link, D. W. Rankin, Paul K. Sims, W. Randall Van Schmus
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The distribution of Middle and Late Proterozoic sedimentary and metasedimentary cover that lies unconformably on Early Proterozoic and Archean crystalline basement has been known for decades, but recent work, employing techniques of paleomagnetic correlation, sedimentology, sequence stratigraphy, and analysis of tectonic subsidence has led to modifications of some long-accepted correlations and tectonic models. Within the context of both older classical studies and this new work, the stratigraphy, correlation, tectonic setting, fossil content, and mineral potential of Middle and Late Proterozoic rocks of parts of the Rocky Mountain, Colorado Plateau, and Basin and Range provinces of the United States are discussed.
A problem common to interpretation of all Proterozoic strata is a widespread lack of fossil control on age and paleoecology, which makes correlations inherently uncertain and interpretation of depositional environments more difficult. We present current hypotheses about these topics and stress the uncertainty of some of our conclusions. The apparent polar wander path for the North American craton, as derived from the Middle and Late Proterozoic sedimentary cover, is central to our modifications of stratigraphie correlation, especially of Middle Proterozoic rocks.
The reader is asked to view the work and summaries presented here in the light of ongoing scientific debate about strata that are chronically stubborn in yielding information. The authors of sections of this chapter include both those who have performed classical studies, which are the foundation of our present understanding, and younger geologists who have been busy refining and modifying early interpretations, using different methods of study. The treatment in this chapter is therefore variable depending on which generation of investigators is speaking.
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This wide-ranging discussion of Precambrian rocks includes contributions from a diverse array of authors actively engaged in investigations of various aspects of U.S. Precambrian geology. Summary discussions by the editors of the five major chapters place these contributions in a logical regional framework. A concluding chapter explores Archean crustal processes from the point of view of lunar and planetary analogies, discusses the significance of Sm crustal provinces, and provides an overview of the development of the southern parts of Laurentia. Accompanying plates include a newly compiled map of the Precambrian rocks of the conterminous U.S., maps showing relationships of the Precambrian geology to magnetic anomalies and to isostatic residual gravity, and a new correlation chart for U.S. Precambrian rocks.