Premium
Sub‐surface CO 2 gas flow in Mars' polar regions: Gas transport under constant production rate conditions
Author(s) -
Thomas N.,
Portyankina G.,
Hansen C. J.,
Pommerol A.
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl046797
Subject(s) - outgassing , sublimation (psychology) , mars exploration program , geology , outflow , martian , polar , atmospheric sciences , geomorphology , astrobiology , chemistry , oceanography , physics , astronomy , psychology , organic chemistry , psychotherapist
Sublimation at the ice‐substrate interface with pressure build‐up is an accepted mechanism for the production of fan deposits on the southern polar CO 2 ice cap on Mars. Fluid dynamics modeling has been used to investigate gas outflow through vents in a CO 2 slab ice. Small (5–25 m in length) fan deposits seen on the annual southern CO 2 ice cap can be produced by a steady‐state in which open vents continuously outgas in response to sub‐surface sublimation generated by diurnal energy input through translucent impermeable (to gas) ice slabs. This would produce diurnally‐controlled deposits which would change orientation with time in response to winds thereby explaining observations made by HiRISE on MRO. Gas flow below the ice can reach up to 25 m/s close to the vent. Dust flow in the sub‐ice cavity has also been computed but velocities are much lower with the main acceleration occurring <0.5 m from the vent. This indicates that erosion is likely to be restricted to the immediate vicinity of the vent unless channels form in the cavity between the ice and the surface.