FACTORS INFLUENCING THE CAPABILITY OF LAVA TO ERODE ITS SUBSTRATE - APPLICATION TO VENUS

There is evidence that a uniquely Venusian type of channel may be at l east partly erosional in origin. A number of published models discuss the erosion process on various planetary bodies. However, these relate to lavas of specifically different compositions. Here a numerical mod el is derived to investigate the sensitivity of the erosion process to various physical parameters of the lava and substrate, placing constr aints on the physical characteristics required to obtain a suitably ra pid erosion rate. The model allows for the effects of latent heat and also considers the presence of a liquid substrate boundary layer betwe en the lava and solid substrate. The results indicate that the thermal erosion process is particularly sensitive to the melting temperature, when the melting temperature is doubled from 700 to 1400 K, the erosi on rate decreases by approximately an order of magnitude. Also, the er osion rate associated with a venusian initial substrate temperature is approximately 1.5 times greater than the equivalent terrestrial one. Mechanical erosion is considered by altering the percentage of latent heat required to melt the substrate; as this percentage is varied from 0 to 100, the erosion rate decreases by about a factor of 2.