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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, E08005, doi:10.1029/2006JE002816, 2007

Cold jets in the Martian polar caps

Hugh H. Kieffer

Celestial Reasonings, Genoa, Nevada, USA

Abstract

Mars seasonal polar caps display dark ice, local darker spots, aligned elongate patches, and radially dendritic forms that reverse albedo contrast. The unexpected variety and sequence of these features are explained on the basis of processes involving CO₂, dust, sand, and H₂O. These processes are largely related to the atmosphere being near its saturation temperature, and they have few terrestrial analogies. In the simplest case the ∼1 m thick seasonal cap, initially dusty, cleans itself and becomes translucent after sunrise and is impermeable over extensive regions except for local vents. The slab ice sublimates at the base and is levitated on high-pressure gas, causing humidity exchange with deeper layers; subslab gas converging toward the vents erodes channels in the soil and ejects this material in high-velocity jets. Recent spectral observations indicate great variety in the details.

Received 20 August 2006; accepted 29 June 2007; published 9 August 2007.

Keywords: Mars; ice; vents.

Index Terms: 5462 Planetary Sciences: Solid Surface Planets: Polar regions; 5464 Planetary Sciences: Solid Surface Planets: Remote sensing; 5422 Planetary Sciences: Solid Surface Planets: Ices; 5445 Planetary Sciences: Solid Surface Planets: Meteorology (3346); 5460 Planetary Sciences: Solid Surface Planets: Physical properties of materials.

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Citation: Kieffer, H. H. (2007), Cold jets in the Martian polar caps, J. Geophys. Res., 112, E08005, doi:10.1029/2006JE002816.

Copyright 2007 by the American Geophysical Union.