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Strong, Nikki1, Wonsuck Kim1, Ben Sheets1, John Martin1, Michael Kelberer1, Chris Paola1, Lincoln Pratson2 
(1) St Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN 
(2) Duke University, Durham, NC

ABSTRACT: An Experimental Study of Predicting Stratal Geometry and Preservation Potential from Relative Sea Level

We compare the efficacy of two measures of relative sea level in predicting stratal geometry and stratal preservation potential during fluctuating base level in an experimental basin. These two measures of relative sea level are, first, the "local" relative sea level (LRSL), i.e. the sum of the rate of eustatic sea level change and local subsidence rate, and second, the shoreline-following relative sea level (SFRSL), i.e. local RSL evaluated at the shoreline as shoreline moves across the depositional surface. These two measures of relative sea level are compared using data from an experiment conducted in the eXperimental EarthScape (XES) at St. Anthony Falls Laboratory, University of Minnesota, an experiment intended as a study of stratigraphic response of a fluvial deltaic system to fluctuations in base level, given passive-margin style subsidence and constant conditions of sediment and water supply. We find that the LRSL curve predicts well stratal preservation of sea level cycles as a function of downstream position in the basin, while the SFRSL curve correlates well to the temporal history of incised valley initiation and development. Furthermore, we find that the sequence boundary (defined by the incised valley floor) was shaped both during the base level fall and rise producing a strongly diachronous surface. This sequence boundary is quite different from incised valley topography at any instant in time and any stratigraphic record of shoreline regression that occurred during base level fall.


AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.