Abstract
The rates at which parts of the geological record have formed can be roughly determined using physical sedimentology independently from other dating methods if current understanding of the processes involved in sedimentology are accurate. Bedform and particle size observations are used here, along with sediment transport equations, to determine rates of transport and deposition in various geological sections. Calculations based on properties of some very extensive rock units suggest that those units have been deposited at rates faster than any observed today and orders of magnitude faster than suggested by radioisotopic dating. Settling velocity equations wrongly suggest that rapid fine particle deposition is impossible, since many experiments and observations (for example, Mt St Helens, mudflows) demonstrate that the conditions which cause faster rates of deposition than those calculated here are not fully understood. For coarser particles the only parameters that, when varied through reasonable ranges, very significantly affect transport rates are flow velocity and grain diameter. Popular geological models that attempt to harmonize the Genesis Flood with stratigraphy require that, during the Flood, most deposition believed to have occurred during the Palaiozoic and Mesozoic eras would have actually been the result of about one year of geological activity. Flow regimes required for the Flood to have deposited various geological cross-sections have been proposed, but the most reliable estimate of water velocity required by the Flood was attained for a section through the Tasman Fold Belt of Eastern Australia and equalled very approximately 30 ms to the -1 (100km h^-1). Case studies were made of the Hawkesbury Sandstone in the Sydney Basin (Australia) and the Coconino Sandstone which is exposed in the Grand Canyon (USA). Both of these sandstones cover thousands of square kilometres. About half of the 250 m thick Hawkesbury Sandstone could have been deposited in about two days according to calculations based on bed forms, with the water flowing over the whole Hawkesbury Sandstone continuously at the calculated velocity of 15 ms^-1. The calculated duration of deposition for the remainder of the sandstone, which includes a minor mudstone lithosome, greatly exceeds the duration of the Genesis Flood, and therefore in context must be grossly in error. Thus known sediment transport equations do not seem to be fully applicable to deposition of all of the Hawkesbury Sandstone if it was deposited during the Genesis Flood. The deposition of the sandstone was, however, much more catastrophic than any deposition observed in the world today if these calculations are accurate. The same conclusion can be reached for other basins, as the bed forms and grain sizes of many of their sandstones are similar to those found in the Hawkesbury Sandstone.