The Interpretation of Lava Flow Morphology

It is postulated that lavas are non-Newtonian liquids with a yield stress and that it is the yield stress which determines flow dimensions. An appropriate theory was developed for the unconfined flow of ideal Bingham liquids on inclined planes. The occurrence of structures similar to levées on lava flows was predicted. The theory was verified by laboratory measurements on flows of suspensions of kaolin. These flows showed similarities to lava flows. Data from lava flows was also found to be in general agreement with the theory which was then used to interpret the shapes of two lunar lava flows. It was possible to estimate yield stresses and flow rates for these lavas.