QUOTE

The results from OMEGA and MER suggest that surface water may have led to production of phyllosilicates early in martian history, and perhaps somewhat later to deposition of hydrated sulfates. Because phyllosilicates and sulfates are found in different parts of the planet, the extent to which their formation might have overlapped in time is an important subject for future work. The acidity that promoted sulfate precipitation likely resulted from sulfur outgassing during volcanic activity. Both the roughly neutral pH suggested by phyllosilicates and the lower pH suggested by sulfates could have produced habitable surface environments; the former may have been more suitable for the origin of life. A future mission to phyllosilicate-rich terrains, followed by sample return from whichever terrain type shows the best overall potential for preservation of biosignatures, could be a good strategy for future Mars exploration. The combined results of the OMEGA and MER investigations illustrate how important international collaboration and associated synergistic analyses could be in such a venture.