Abstract: Absolute Sea Level Curves: Implications for Sequestered Water Volumes

David Rowley, Paul J. Markwick

"Absolute" sea level curves are those that estimate the height of sea level relative to today as a function of time. Such curves make explicit predictions as to changes in volume of the ocean basins and sequestering reservoirs. We use the Haq et al. (1988) curve as a case study to demonstrate that it is possible to compute directly the actual volumes of water that need to be sequestered from the ocean basins to account for the deviation of the short from the long term curves. Based on this analysis we show that the Haq et al. (1988) curves requires from Late Jurassic to Late Eocene at approximately 5 my frequency that volumes greater than presently sequestered by ice in Antarctica are needed to account for their interpreted sea level curves. Some workers have described possible glacia or glacial-marine sediments from various regions of the world through the Mesozoic and Cenozoic. A review of both the specific geology and of alternative rafting mechanisms indicates to us that there is no unequivocable observational basis upon which to suggest any Mesozoic to pre-latest Eocene glaciations. Unfortunately the inaccessibility of most of Antarctica due to present day ice precludes complete certainty in this analysis. We therefore developed a corollary technique based on Oxygen isotope fractionation that allows the retrodiction of a ^dgr¹⁸O history based

on any "absolute" sea level curve. Comparison of the ^dgr¹⁸O history retrodicted by Hag et al. sea level curves with that recorded at various DSDP and ODP sites indicates that there is little or no correlation between the retrodictions and observations either in timing or magnitude, negating their interpretation.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994