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N.S. Duxbury (JPL), I.A. Zotikov (Inst. of Geography), K.H. Nealson (JPL)
If future Mars Surveyor Missions discover water under the martian North polar cap, we propose that this water was on the martian surface before the formation of the cap and did not freeze all the way to the bottom. Recent MGS MOLA date revealed that the North polar cap is thinner than previously estimated. To reach the melting isotherm the ice has to be at least 4 km thick, whereas the maximum cap thickness was derived to be only about 3 km. We have developed a comprehensive numerical model for the perennial glaciation of the Antarctic Lake Vostok under the assumption that it was initially an open lake and applied it to Mars. A significant result of our model computations for Antarctica (which parameters are much better constrained than that for Mars) is that shortly after the beginning of glaciation (in only about 3300 years) the internal heat flow began to dominate the external temperature decrease, which we considered as a function of the ice thickness. Hence, the exact values of the plummeting external temperature were not needed to substantiate our hypothesis that an initially open lake on Mars did not freeze all the way to the water bottom if it was deeper than only about 63 m. Thus, the sub-ice water is older than the cap itself. Such an environment would be an ideal candidate for extant or extinct life on the red planet. This argues for a drilling mission at the martian North polar cap.
The work performed at JPL was funded by NASA Astrobiology program.
The author(s) of this abstract have provided an email address for comments about the abstract: nsd@scn1.jpl.nasa.gov