How to displayed fixed menus, extracted from the main menu? I am using a Bartik subtheme, and would like to split the main menu into 4 smaller menus, and display them in the four footer columns, side by side. I would like the same menus to be displayed on all pages. 

How would I do this?
If you go to admin/structure/menu/add and add four menus (Footer 1, Footer 2 ...), four blocks of the same name will also be created. Then go to your Main Menu and move the links into the new menus you have created.

Place these blocks where you want them at admin/structure/block and modify your stylesheets to make sure they display the way you want.