Red Rock Tumbler
It's a Grind to Make Mars Red!
“Mars should really look blackish, between its white polar caps, because most of the rocks at mid-latitudes are basalt. For decades we assumed that the reddish regions on Mars are related to the water-rich early history of the planet and that, at least in some areas, water-bearing heavily oxidized iron minerals are present,” said Dr. Merrison, of the Aarhus Mars Simulation Laboratory, Denmark.
In their recent laboratory study, scientists at the Mars Simulation Laboratory have pioneered a novel technique to simulate the sand transport on Mars. They hermetically sealed sand (quartz) samples in glass flasks and mechanically “tumbled” them for several months, turning each flask ten million times. After gently tumbling pure quartz sand for seven months, almost 10% of the sand had been reduced to dust. When scientists added powdered magnetite, an iron oxide present in Martian basalt, to the flasks they were surprised to see it getting redder as the flasks were tumbled.
“Reddish-orange material deposits, which resemble mineral mantles known as desert varnish, started appearing on the tumbled flasks. Subsequent analysis of the flask material and dust has shown that the magnetite was transformed into the red mineral hematite, through a completely mechanical process without the presence of water at any stage of this process,” said Dr. Merrison.
Scientists worldwide, aided by new missions and improved instrumentation reaching the planet, will continue developing new improved computer models and Earth-bound simulators to try to pierce through the red planet’s mysteries.
“By simulating the conditions and developing accurate analogues of the Martian environment, we will certainly gain a deeper understanding of its dusty nature. In particular, developing better analogues of the Martian surface and atmosphere is vital in interpreting observations made on Mars by landers as well as pioneering the next generation of experiments to be flown,” said Dr. Merrison.
This work has been accepted for publication in; “Mineral alteration induced by sand transport; a source for the reddish colour of Martian dust,” J. P. Merrison, H. P. Gunnlaugsson, S. Knak Jensen, P. Nornberg, Icarus, 191, 568-580 (2009).