| I explore the relationships between lava tube morphology, estimates of lava viscosity and effusion rates, and the mechanism of lava tube formation. I calculated effusion rates for extinct lava tubes using three-dimensional lava tube maps, and viscosity modeling utilizing data from collected samples. Lava tube lengths, effusion rate estimates, and thermal modeling were used to evaluate the mechanisms of lava tube formation. Lava tube lengths vs. cross-sectional radii show a positive correlation. This reflects the positive correlation observed between lava flow lengths and effusion rates in active Hawaiian channel-fed flows. Lava tube length vs. effusion rate estimates were compared with data for Hawaiian channel-fed flows. The two data sets overlap and have parallel trends. This suggests that the lava tubes studied formed by the roofing-over of channel-fed flows or had segments of channel-fed flow. Estimates of the lengths and mean cross-sectional radii of lava tubes can be used to evaluate whether or not extinct lava tubes formed by the roofing-over of channel-fed flows. Length and radius estimates of extraterrestrial lava tubes could provide insight on their formation mechanism independent of in situ studies. |
