Dan, you slay me.... heh.
But seriously, if this is more fundamental than just a neat idea, it would have serious implications for life on Mars.
No granites -> no feldspar -> no weathering to clay -> no life?
I'm probably being far too absolute here but without continental recycling and widespread conventional liquid water weathering, there just ain't much clay to be had on Mars.
This is the part where NH walks in and says nice idea kid but.....