Atmosphere-crust coupling on Mars and implications for habitability

Pieces of the crust of Mars that have come to Earth as meteorites are a powerful source of information on the geological evolution of the red planet. Despite all but one of these meteorites being igneous rocks, they also have the potential to provide unique insights into the properties of the Martian atmosphere, hydrosphere, and possibly also its biosphere.

The current focus of work at Glasgow is on using the meteorite record to constrain the history of water and carbon dioxide in Mars’ atmosphere. Water can be analysed directly because it has been trapped within primary (magmatic) minerals such as apatite and olivine, and within products of aqueous alteration of the meteorites (eg phyllosilicates). The deuterium/hydrogen ratio of this water can be used to quantify the rate at which the planetary reservoir has been lost to space, and specifically to test the hypothesis that much of the water had escaped within the first 500 million years. Carbon dioxide is trapped within carbonate minerals that occur in several groups of Martian meteorites. The petrographic context of these minerals suggests that carbon dioxide was sequestered from the atmosphere by reactions with crustal rocks. The scarcity of carbonates however indicates that early Mars may not have had a thick carbon dioxide-rich atmosphere.

Martian meteorites will reveal much more about the history of the planet as ever more sophisticated analytical techniques are developed, and they will acquire a new significance as the international community plans for the return of samples from Mars in the next 20-30 years.

Tea and coffee will be served after the seminar.