VOLCANO-ICE INTERACTIONS AND THE EXPLORATION FOR EXTANT MARTIAN LIFE

Introduction: Recent discoveries revealed terrestrial colonies of microbes both in 349 K geothermal groundwater located at a depth of 2800 m, beneath glaciers in the Canadian Arctic and subglacial lakes in Antarctica at a depth >3 km. The existence of extremophiles in these subsurface environments has opened up important new directions in the exploration for Martian life. Consistent with NASA's programmatic initiative to "follow the water," exploration for extant life has focused on the search for zones of subsurface water. Previous authors identified environments for liquid water in the region of the Martian North Polar Cap of Mars, including the melting at the base of ice sheets and magma-ice interactions. Such magma-ice interactions in Iceland have created landforms that may serve as possible analogs for Martian landforms observed in some Viking and MOC images.

Volcano-Ice Interactions in Iceland as Analogs for Mars: Subglacial volcanism, associated jökulhlaup outfloods, and pseudocraters/rootless cones are examples of volcano-ice interactions observed in Iceland that could also exist on Mars. The Grímsvötn geothermal area located on Iceland’s Vatnajökull Glacier boasts a network of active subglacial volcanoes and fissures. The extensive geothermal system present beneath the ice cap is thought to be responsible for repeated jökulhlaup (glacial outflood) events in the region. Additionally, pseudocraters (or "rootless cones") are present in periglacial areas where lava flows have been extruded over ground ice or shallow aquifers. In such regions, fields of small volcanic cones form by phreatic (steam) explosions. The potential for identifying similar geomorphic features on Mars using MOC-scale imaging is great.

Methods: We conducted a survey of Viking orbiter and Mars Orbiter Camera (MOC) images for the region north of 70° N. Several promising sites provided evidence for localized volcano-ice interactions along the margin of the North Polar cap. A detailed morphological feature comparison (incorporating MOLA topographical data) with terrestrial analogs is presently underway.