I studied corrosion for a short while. My mentor, Dr. Abraham Benderly informed me that corrosion was often a synergistic process requiring multiple components. In our case, an HCN and NH3 gas recycle stream would not corrode good stainless steel. But if water was present, the combination could eat through a centimeter of Hastelloy C in a day. They had to make the whole distillation tower out of Zirconium, consuming 1/5 of the total world stockpile. (Its mostly used in Aerospace, great stuff).

In the article that Nick Hoffman kindly posted for me, they corroded basalt containing Olivine with weak acid solutions. They purposefully exposed the samples to the Earth atmosphere to equilibrate. My question is if any corrosion (weathering) experiments have been done on Olivine that excluded oxygen. Mars has such a low amount of oxygen, that if it was essential for the corrosive reactions, then Olivine might be much more stable on Mars, and its widespread presence at the surface would not be paradoxical.