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Mars at very low obliquity: Atmospheric collapse and the fate of volatiles
Author(s) -
Kreslavsky M. A.,
Head J. W.
Publication year - 2005
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 - 10.1029/2005gl022645
Subject(s) - geology , mars exploration program , sublimation (psychology) , martian , atmosphere of mars , quasiperiodic function , atmosphere (unit) , atmospheric sciences , astrobiology , physics , meteorology , psychology , psychotherapist , condensed matter physics
The obliquity of the Martian spin axis is known to undergo quasiperiodic oscillations superposed over chaotic long‐term variations. It is probable that within past history there were geologically long periods when the obliquity oscillated around low (10–15°) mean values. During such low obliquity epochs the climate system is controlled by deposition of permanent solid CO 2 deposits in the polar regions. With a simple season‐resolved energy balance model, we show that as the atmosphere collapses, surface topography plays a major role in CO 2 condensation and sublimation processes, defining distribution and dynamics of CO 2 deposits. Thick CO 2 deposits are formed at steep pole‐facing topographic slopes at moderately high latitudes, not at the poles. The total mass of the deposits is not a function of obliquity, but strongly depends on the pre‐history of the climate system. We outline criteria to identify such low‐obliquity epochs in Mars history.