The Proceedings of the Eighth International Conference on Creationism (2018)

bedding planes in typical vertical sequences between continental basement and the earth’s surface as illustrated in Figure 7. What conceivable mechanism could have produced such high frequency modulation of the sediment transport and deposition processes to yield so many distinct individual beds that commonly display huge lateral extent, yet with laterally uniform composition and character? The vast numbers of tsunamis that catastrophic plate tectonics appears to demand seems to be the answer. The length of each of the 16 subduction zone segments assumed in the model that locked and slipped every 96 minutes to generate a tsunami was 1,500 km. This produced a total of 36,000 tsunamis over the span of 150 days. But if we look at preset-day subduction zones for guidance, it is likely that the typical segment length was much shorter. Reducing the segment length to half of that assumed doubles the total number of mega-tsunamis to 72,000. Since these tsunamis are large enough to propagate at least once around the earth before their amplitude becomes small, they appear to provide a viable explanation for the modulated character observed in the vertical structure of the sediment record, especially at the bed level. In terms of the Flood and it brief time scale, it is difficult to imagine an alternative that could produce this high frequency modulation. What insight might the calculation included in this paper provide as to the mechanism or mechanisms that may have been responsible for the megasequence structure of the fossil-bearing sediment record? The short answer is that this rather primitive calculation yields no hint of the sort of large scale pattern of transgression and recession of ocean water that seems to be implied by the megasequence morphology. The secular community generally interprets the megasequence structure to be the result of a variation in global sea level. Indeed, a rise and fall in sea level several times during the Flood, combined with the tsunami activity, does appear to offer a viable explanation. Other modeling work indicates that the rapid global tectonics and associated flow of rock inside the mantle during the Flood does lead to significant time-variation in global sea level (Baumgardner, 1994). What about the issue of the continental shields? The existence so many shield areas today testifies to the reality of extreme erosion of the igneous bedrock over vast portions of today’s continents. These shield areas are remarkably flat with little or no erosional channeling and generally display little or no sedimentary deposition subsequent to their intense erosional beveling. In the context of the Flood, these areas would seem to be obvious candidates as source areas for at least some of the sediment we find elsewhere on the continental surface. A major issue, however, is an erosional mechanism sufficiently potent to erode resistant crystalline bedrock to depths of up to a kilometer or more within the time span of the Flood and to do so in such a uniform manner across such laterally extensive areas. The frequent, large-amplitude tsunamis in this numerical model appear adequate for such a task. Indeed, it is difficult to imagine an alternative mechanism capable of accomplishing such intense and laterally extensive erosion to produce surfaces with such astonishing flatness. In the calculation described in this paper it is noteworthy, however, that almost all the bedrock erosion occurs on the continental slope, with very little in the continental interior. One possible explanation is that the dynamic surface topography generated by stresses from flow of rock inside the mantle is not yet included in this formulation. Earlier calculations of the rapid tectonics during the Flood (e.g., Baumgardner 1994) reveal that deflections of the earth’s surface by many kilometers arise from the flow of rock inside the mantle. When those dynamic up-and-down motions of the continent surfaces are included it is likely that significant bedrock erosion will indeed occur within the continent interiors. This issue merits priority in future numerical investigations. Regarding an explanation for why so much sediment is emplaced on top of the continents when their surfaces mostly lie above sea level, these calculations provide especially helpful insight. The water speeds and depths are sufficient to sustain the level of turbulence needed to suspend the large volume rate of sediment produced by cavitational erosion, to transport it to distant locations, and to deposit that sediment on the continent surface in thicknesses exceeding more than a kilometer over vast areas. The tsunami- driven flow accounts not only for erosion of significant volumes of sediment but also its emplacement above sea level on top of the continents in coherent patterns with large horizontal dimensions and thicknesses. The model thus seems to account in a powerful way for the emplacement of the sediment on top of the continental surface in broad agreement with observations. The tsunami mechanism also provides a trivially simple explanation for the runoff of the Flood water from the continental surface. As the gravitational potential energy from the sinking lithospheric slabs and rising mantle plumes which had been driving the runaway motions begin to be significantly depleted, the surface plate speeds diminish, the tsunamis decrease in frequency and amplitude, the flow rates of the water currents on the continents plummet, and the water that had repeatedly traversed the continental surface simply drains away, back into the ocean basins. The tsunami mechanism provides trivially simple answers to the commonly asked questions as to the source of the Flood waters and where these waters went after the Flood. The answers to both questions, of course, are the ocean basins. 3. Future model enhancements It is important to emphasize that the numerical model described in this paper is highly simplified relative to the real earth and includes Baumgardner ◀ Large tsunamis and the Flood sediment record ▶ 2018 ICC 303 Figure 7. Photo of a common characteristic of the sediment record, that of beds separated by bedding planes.