RELATING THERMAL INERTIA OF BASALTIC LAVA FLOWS TO THEIR TEXTURE

Remote sensing of planetary bodies provides invaluable data about their surfaces. Due to limitations in spatial resolutions, it is currently not possible to distinguish the variety of surface textures of lava flows. The surface texture of a lava flow, including roughness and porosity, can inform on the emplacement and rheology of the flow. A property that could be used to distinguish between surface textures is thermal inertia, which is a measure of a material’s resistance to temperature change over time, for example over the diurnal (day-night) cycle. Thermal inertia cannot be determined remotely but an estimate can be determined from apparent thermal inertia (ATI) calculated from the albedo and diurnal temperature difference of the flow surface. This project aims to relate the surface texture of several Holocene basaltic lava flows to their thermal inertia. The flows are Carrizozo, Paxton Springs, and Aden Crater which are in central, western, and southern New Mexico respectively. Laboratory analysis of collected samples included petrography, geochemistry, density, heat capacity, thermal diffusivity, and monitored cooling experiments. These thermal inertia measurements are compared with values of ATI derived from thermal images collected in the field with a Forward Looking Infrared (FLIR) camera, and satellite remote sensing data. Laboratory data suggests that thermal inertia could be used to differentiate between pahoehoe and a’a’ texture, but we found that they are not differentiable with apparent thermal inertia derived from field and satellite data. While ATI cannot distinguish between surface textures, it could provide a rough estimate of sample porosity.