Evidence for and Against Sea-Level Changes from the Stable Isotopic Record of the Cenozoic
Douglas F. Williams, 1988. "Evidence for and Against Sea-Level Changes from the Stable Isotopic Record of the Cenozoic", 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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The stable oxygen isotope record for the Cenozoic is characterized by a series of large third-order steps of +1 per mil superimposed on a long-term second-order trend. This second-order trend accounts for a δ18O change of nearly +4 per mil from the early Eocene into the Neogene. The second- and third-order changes in the δ18O signal are driven primarily by a combination of glacio-eustatic sea-level and ocean paleotemperature changes. These changes are global responses to evolving circulation and climate patterns. Timing of the δ18O events is in good agreement with the seismically defined changes in the coastal-onlap curve (Vail and others, 1977). Agreement in the timing of events supports a common mechanism, perhaps that glaciation is apparent throughout much of the record and certainly intensified beginning in the Neogene. Agreement is not good between the magnitudes of apparent changes in sea level using the EXXON onlap record and oceanic δ18O events. Consideration of the δ18O, ice volume, and sea-level relationships during the Pleistocene suggests that sinusoidal eustatics, i.e., the rise and fall of sea level being equal, is not a good assumption at fourth- and fifth-order sea-level events. Although interpretation of the δ18O record is not without its assumptions and limitations, it offers an independent geochemical check on seismically defined changes in stratal patterns.
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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.