--> Abstract: The Significance of Transgressive Erosional Surfaces in Sedimentary Basins, by Yuval Bartov and Dag Nummedal; #90039 (2005)

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The Significance of Transgressive Erosional Surfaces in Sedimentary Basins

Yuval Bartov and Dag Nummedal
Colorado School on Mines, Golden, CO

Erosional surfaces connected to shoreline transgressions are recognized in the rock record and attributed to shoreface erosion induced by wave action. By contrast, the linearly shaped incised valleys that are controlled by base level variation and stream flow are subjected to climate and basin physiography thresholds. Thus the related erosional processes are confined to the valleys. Transgressional ravinement, however, creates a surface that is dependant on the shoreline trajectory and wave energy. Erosion of exposed surfaces during sea level low-stand is virtually absent between valleys, while transgressive erosion is wide spread and erodes an entire shoreface. This paper suggests that transgressions constitute a significant erosional process within basins, from a volumetric perspective. The erosion that occurred as a result of a 0.8 m lake level rise at the Dead Sea in one month was measured by comparing the profile before and after the erosion took place. The result is a 2.5X106 cubic/m volume of eroded shoreface sediments, which is similar to the volume of three incised valleys in the basin that are active over 15,000 years. This provides an analog to the extensive erosional surface that resulted from a 30 m lake-level rise in the mid-Holocene. This example points to the significance of such process not only in low wave energy lacustrine settings but also as a dominant surface in continental margins such as the New Jersey margin and the Texas coast.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005