Volcanic rootless constructs (VRCs) are products of explosive lava–water interactions. VRCs are significant because they imply the presence of active lava flows and an underlying aqueous phase (e.g., groundwater or ice) at the time of their formation. This information is valuable for locating fossil hydrothermal systems and exploring the relationships between climate, water stability and abundance, weathering environments, and the development of habitable niches in extraterrestrial environments.
The architecture, structure, and emplacement chronology of VRCs in the 1783–1784 Laki lava flow in Iceland were investigated using tephrostratigraphy, Differential Global Positioning System (DGPS) measurements, remote sensing, and Geographic Information Systems (GIS). The geospatial distribution of rootless eruption sites were also analyzed using statistical methods to quantify their patterns of spatial organization and infer the geologic processes of their formation.
Employing terrestrially validated morphological and geospatial criteria, analogs to Icelandic VRCs were identified in the Tartarus Colles region of Mars. The VRC groups and associated geologic units were mapped using remote sensing and GIS. Impact cratering statistics were used to constrain the age of the VRC groups and thermodynamic models of lava–permafrost interactions were used to estimate paleo-ground ice table depth, calculate mobilized (i.e., melted and/or vaporized) water volumes, and infer obliquity-driven climate conditions.