A study of physical processes on the surface of mars and their possible bearing on the detectability of carbonates

Abstract

The absence of carbonate features in the infrared spectra of the Martian surface is a wondering issue. Mars is sending us contradictory messages in this respect. On the one hand, images of the Martian surface show structures strikingly reminding of possible bodies of standing water, which could favour the accumulation of sedimentary deposits in the past. On the other, the apparent absence of carbonates in the surprisingly homogeneous fines covering the Martian surface and suspended in the atmosphere, raises the question, where the carbonates could hide now, had they ever formed on Mars. All this makes the essence of the so-called “missing carbonates” quest. We discuss here the photolysis of carbonates by ultraviolet solar radiation, and show that the process should be effectively balanced by readsorption of the atmospheric carbon dioxide on the remaining calcium oxide surface. Hence, photolysis could not account for the failure of searches for carbonates on the Martian surface. Other solutions to the problem of “missing carbonates” should then be investigated.