USING CINDER CONE MORPHOLOGY TO CONSTRAIN AGE (SAN FRANCISCO VOLCANIC FIELD REU)
The effect an agglutinated rim has on cone morphology evolution is explored with a surface process model on idealized cones. Weathering processes are simulated through numerical modeling (two-dimensional nonlinear diffusion) using two different sediment transport rate (k values, one for the cone flank and one for the ring of agglutinate on top. Non-agglutinated cones show a greater decrease in height and increase in width over time, resulting in a lower height-to-width ratio and a higher rounding profile than agglutinated cones. The presence of an agglutinate top lessens the amount of rounding, producing a “neck” as the cone flank erodes. Thus, the agglutinated cones have “younger” height-to-width ratios. Sand cones constructed and eroded through analog modeling show profiles that are similar to the numerical model results, with the spray-adhesive-agglutinate cone having a prominent neck and a greater height-to-width ratio.
Cone erosion profiles are altered by presence or lack of agglutinate and rate of sediment transport, which is dependent on climate. Height and width measurements of a cone, the cone’s estimated age, and the k values corresponding to the climate of the cone’s region, can be used to make a calculation of relative age. This is especially beneficial for gathering of age data of cones in remote or hard to access locations, including locations on other planets.