BRIDGE, John, Dept. of Geology, Binghamton University, P.O. Box 6000, Binghamton, NY 13902-6000, USA; BEST, Jim, Dept. of Earth Sciences, University of Leeds, Leeds LS2 9JT, West Yorkshire, UK

Experimental studies of the formation of planar laminae by migration of low-relief bed waves over aggrading upper-stage plane beds show that the average thickness of laminae at a point increases with both aggradation rate and the variance of the heights of bed waves passing that point. In general, the preserved laminae represent only a small proportion (generally less than 50%) of the height of the largest bed waves in the population. The theory developed by Paola & Borgman (1991), relating the probability density function of stratal thickness to that of bed-wave height for the case of no net aggradation, was adapted for aggrading conditions and shown to agree well with data. These results suggest that it may soon be possible to reconstruct the distrib ution of bed-wave heights that passed a given point from the distribution of thicknesses of planar laminae or cross sets, provided that estimates can be made of aggradation rate and length and celerity of bed waves.