Monday, June 17, 2013
Investigations of Lava Flows on Earth and Mars
July 24, 2013
Dr. David Crown
Planetary Science Institute
The Geologic Histories of Mars, Venus, and Io
The Tharsis volcanic province on Mars contains vast lava plains surrounding the largest shield volcanoes in the solar system. Current research examines the styles and sequences of volcanism in southern Tharsis using imaging, topographic, and compositional datasets acquired by recent spacecraft missions. This work combines traditional geologic mapping with detailed flow field mapping to document observations important for interpreting volcanic processes and geologic history. The morphology of lava flow lobes reveals the nature of flow emplacement processes and is used to assess flow field development and stratigraphy. Populations of small, superposed impact craters are used to derive relative and absolute age constraints for individual flows and flow sequences.
Accurate interpretations of volcanic processes on other planets are dependent upon field and remote sensing analyses of terrestrial analogues. New capabilities for field analyses of active lava flow emplacement are being utilized to qualitatively and quantitatively characterize lava flows in order to directly link surface morphology to observed emplacement processes, providing a robust foundation for interpretations of planetary volcanic features. A combination of ground-based scanning LiDAR, thermal imaging, and high-definition video and time-lapse photography provide rapid acquisition of high-resolution spatial and high-precision thermal datasets for advancing tube-fed pahoehoe flows in Hawaii. High-definition video and time-lapse photography document the nature and changes in flow behavior and are used for interpretation and analysis of thermal and topographic data. The thermal data show the distribution of lava surface temperatures and are used to identify new lava breakouts and to define and chart the evolution of discrete lava units. Repeat LiDAR scans at regular intervals during flow emplacement are used to document morphometric characteristics of individual flow elements and compound lobes, directly link quantitative morphometric measurements to flow characteristics such as flow morphology and temperature, and calculate flow volumes and advance rates.