Quantifying the amount of water in Martian Hydrated Minerals

Quantifying the amount of water on present-day Mars is important for understanding Mars' history, including its past climate and the potential for life. There are several sinks and loss mechanisms for water on mars that help explain why there is significantly less water on Mars today than there used to be in the past. 

In this study, we estimated the amount of water that is stored in hydrated minerals on Mars. Hydrated minerals include varying amounts of water in their chemical compositions, and have been detected by both Martian orbiters and rovers. In order to quantify the amount of water in Martian hydrated minerals, we estimated the thicknesses and densities of rocks that contain hydrated minerals on Mars, and we estimated the percentage of water by weight (wt.% water) of both the ice-free surface and the subsurface of Mars.

Our best estimate for the volume or water stored in hydrated minerals on Mars is about seven times larger than the water currently stored in the Martian polar caps and near-surface ice. Hydrated minerals are a significant sink for Martian water.