PSI Scientists Analyze Large Concentration of Lava Tubes on Martian Volcano Alba Mons

Category: Cover Story

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Lava tubes are high priority targets for in situ exploration of Mars, with the potential to provide access to subsurface cavities that could facilitate scientific studies of the Martian subsurface as well as provide shelters for future astronauts. Martian lava tubes could allow for collection of important rock and water/ice samples for studies of the geology, climate history, and astrobiological potential of Mars. 

In a Special Issue of the Journal of Geophysical Research entitled Exploring Planetary Caves as Windows into Subsurface Geology, Habitability, and Astrobiology, David A. Crown, Stephen P. Scheidt, and Daniel C. Berman of PSI document the characteristics of a distinctive population of large lava tube systems that dominate the western flank of the volcano Alba Mons. 

Alba Mons is an enormous Martian shield volcano located in the northern part of the Tharsis Volcanic Province, which contains a series of large volcanoes (including Olympus Mons) and surrounding lava flow fields. Alba Mons is more than 1000 x 1000 kilometers across (with a greater surface area than Olympus Mons), but exhibits only approximately 6 kilometers of relief and extremely low flank slopes (approximately 1 degree). Comparable values for Olympus Mons are 640 x 840 kilometers, relief of 21.9 kilometers, and flank slopes of 5 degrees. 

In the course of geologic mapping studies of the Alba Mons’ western flank and summit region, the three PSI scientists have analyzed what is likely the greatest concentration of large lava tubes on Mars. Identification and mapping of Alba Mons’ lava tube systems utilized both imaging and topographic datasets of the Martian surface from multiple NASA missions. Lava tube segments exhibit chains of collapse depressions, sinuous ridged forms, or both, with chains of collapse depressions often occurring along ridge crests. The study mapped more than 300 lava tube segments with individual lava tube systems extending for up to approximately 400 kilometers and with a total length in the study area of approximately 12,000 kilometers. 

The recently published paper compares the characteristics of the Alba Mons’ lava tubes, which are estimated to be about 1.9 to 2.5 billion years old (from Mars’ Early Amazonian Epoch), to both lava tubes on Earth and to lava tubes in the younger southern part of the Tharsis Volcanic Province. 

Less than half of the total length of the currently mapped lava tubes at Alba Mons shows evidence for surface collapse (similar to collapse pits and skylights associated with lava tubes on Earth). This suggests the potential for significant subsurface cavities in the shallow Martian subsurface and for an array of different cavity environments. Given the ranges in elevation and latitude over which lava tubes have been identified, Alba Mons should host numerous significant sites for exploring the geology of Mars.

This research was supported by a grant from NASA’s Mars Data Analysis Program.  

mars lava tubes
mars lava tubes

Lava tubes on the western flank of Alba Mons, Mars shown in Context Camera (CTX) (~5 m/pixel) images. Top: A group of volcanic ridges with chains of collapse depressions along the ridge crests (arrows). Bottom: A lava flow (fl) is deflected by the ridged topography of a lava tube system (t) that is identified by discontinuous chains of collapse depressions. From Crown et al. (2022). 

CTX Image Source: NASA/JPL/Malin Space Science Systems.