The planetary scientists have been talking for months about the olivine on Mars. Olivine is a mineral that is easily decomposed by water. Olivine is not uncommon here in the San Francisco Bay Area due to the San Andreas fault (California is at the junction between two tectonic plates.). Olivine comes from deep within the Earth's mantle and is transported to the surface along the fault line (olivine is also found near volcanoes). The San Andreas rift zone is a nice place for hiking where the pretty green olivine rocks can often be found. The olivine samples that I've found are often quite crumbly due to weathering. The Mars Global Survey spacecraft has discovered that olvine is very common all across the surface of Mars. Supposably there is heaps of it along the Valles Marineris. A theory based upon the general presence of olivine is the Martian surface has been bone dry for 3.5 billion years. This is just another stake in the heart of the "warm and wet theory". Pretty soon only the screwballs and professional liars will argue that there is liquid water on the surface of Mars.

Gary