An international research team led by the Planetary Science Institute has found evidence that indicates that approximately 2 billion years ago enormous volumes of catastrophic floods discharges may have been captured by extensive systems of caverns on Mars, according to J. Alexis Palmero Rodriguez, PSI Research Scientist,
Rodriguez and the research team came to this conclusion after studying the terminal regions of the Hebrus Valles, an outflow channel that extends approximately 250 kilometers downstream from two zones of surface collapse.
The Martian outflow channels comprise some of the largest known channels in the solar system. Although it has been proposed their discharge history may have once led to the formation of oceans, no one knows the ultimate fate and nature of the fluid discharges. There is also a controversy about how these outflow channels came to be. Theories range from surface erosion by glaciers, debris flows, catastrophic floodwaters, or even lava flows.
The team’s work documents the geomorphology of Hebrus Valles, a Martian terrain that is unique in that it preserves pristine landforms located at the terminal reaches of a Martian outflow channel. On Mars outflow channels generally appear highly resurfaced, or buried, at other locations on Mars.
Rodriguez and his co-authors propose in an article titled “Infiltration of Martian overflow channel floodwaters into lowland cavernous systems“ published in Geophysical Research Letters that large volumes of catastrophic floodwaters, which participated in the excavation of Hebrus Valles, may have encountered their ultimate fate in vast cavernous systems. PSI Senior Scientist Mary Bourke and Research Scientist Daniel C. Berman are co-authors on the paper.
They hypothesize that evacuated subsurface space during mud volcanism was an important process in cavern development. Mud volcanism can expel vast volumes of subsurface volatiles and sediments to the surface. But because evacuation of subsurface materials generally occurs within unconsolidated sediments resulting caverns are transient and mechanically highly unstable.
This muddy area could develop a cave system because at that region there is permafrost. The area having a typical temperature of -65 degrees Celsius (-85 degree Fahrenheit) and this gives mud a mechanical strength similar to that of limestone. Limestone rocks host most of the terrestrial cavern systems.
Possible cavern have been recently identified on Mars and their existence has caught much scientific and public attention because of their potential as exobiological habitats. However, their age and dimensions remain uncertain. The discovery of vast caverns that existed in ancient periods of Mars shows that these habitats may have in fact existed during billions of years of the planet’s history.
This Mars research was funded by a grant to PSI from the NASA Mars Data Analysis Program.