There is no one mineral content that characterizes north or south. It varies greatly by location within each region.
http://www.mgwater.com/mgrank.shtml#ordered
In addition, science cannot find notable variations in pizza crust quality based on mineral content of water:
http://slice.seriouseats.com/archives/2010/01/does-nyc-water-make-a-difference-in-pizza-quality.html
Good pizza requires “know how” to make, and a lot more people up north know how to make it.