Late Paleozoic Transgressive-Regressive Deposition
Published:January 01, 1988
Charles A. Ross, June R.P. Ross, 1988. "Late Paleozoic Transgressive-Regressive Deposition", Sea-Level Changes: An Integrated Approach, Cheryl K. Wilgus, Bruce S. Hastings, Henry Posamentier, John Van Wagoner, Charles A. Ross, Christopher G. St. C. Kendall
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Approximately sixty transgressive-regressive depositional sequences are present in Carboniferous and Permian shallow-marine successions on the world's stable cratonic shelves. These sequences were synchronous depositional events that resulted from eustatic sea-level changes. Based on currently available age correlations of rapidly evolved late Paleozoic tropical, subtropical, and temperate shelf faunas, the sequences on different cratonic shelves were time equivalent. These transgressive-regressive sequences averaged about 2 million years and ranged from 1.2 to 4.0 million years in duration.
Local depositional conditions are important in controlling sedimentary patterns on different cratonic shelves. These conditions are affected by changes in sea level, strandline position, and drainage base level and are reflected in the sedimentary record. Because midsize sea-level fluctuations are usually widely identifiable in the stratigraphic record, they are useful aids in correlation. They are particularly helpful between regions that have contrasting depositional conditions, such as between a carbonate shelf starved of clastic sediments and a clastic-dominated shelf on which carbonates are rare.
The appearance of new species and genera generally occurs above unconformities that signal new marine transgressive events and new depositional sequences. The durations of the hiatuses between these transgressive-regressive sequences are difficult to estimate. The hiatuses may represent cumulatively as much time, if not more, than the rock record. The numerous worldwide synchronous unconformities marking hiatuses of considerable duration within late Paleozoic shelf strata suggest that the fossil record may be very incomplete and preserves mostly biota that were extant during times of high sea level. Such an incomplete fossil record could easily be misinterpreted as a punctuated evolution having a highly irregular mutation rate.
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Sea-Level Changes: An Integrated Approach
Sea-Level Changes: An Integrated Approach - In October 1985, SEPM sponsored a four-day conference entitled ?Sea-Level Changes ? An Integrated Approach.? The purpose of the conference was to provide a forum for an interdisciplinary exchange of ideas on sea-level changes and to provide an opportunity for integrating various types of evidence in approaching unresolved issues. The conference was successful in bringing together scientists from industry, academia, and government, representing all of the major geosciences disciplines. Presentations of many new papers, plus significant releases of data that were previously held proprietary, provided fertile ground for discussion. This much-cited volume represents the best of the material presented at the conference. Includes the early ?Vail? chart.