It MEANS something that is only on 2% of the surface and 98% is free of it. What I have been arguing is that the articles are HIGHLY misleading to imply the olivine is found all over Mars. The fact is it is ALMOST ENTIRELY IN THE OLDER SOUTHERN HEMISPHERE. There are only a few isolated outcrops in the younger northern hemisphere, such as Nili Fossae.
I'm suggesting it is no coincidence that the northern hemisphere is also where there is evidence of a former ocean, where there is current evidence of debris covered glaciers, and where the youth of the lava flows suggest volcanic eruptions are ongoing.
The original article claiming olivine over large parts of Mars came out three years ago.
I doubt that most Mars scientists would agree with the view that Mars never had any periods where there were large amounts of liquid water after 3.6 billion years ago. For one thing the dating of several of the large apparently water cut channels date to after this time.
Bob Clark
Space/Science » in reply to No. exactly
Look at the facts.