I don't doubt that rocks have similar compositions throughout the world, but even a cursory examination of the areas from a distance reveals many differences. F

I don't doubt that rocks have similar compositions throughout the world, but even a cursory examination of the areas from a distance reveals many differences. For one, the US southwest doesn't have huge swaths of fine sand. US southwest vs Saudi Arabia @ same scale http://imgur.com/a/OkRuI http://imgur.com/a/OkRuI