re: Where to search for evaporites on Mars.
You don't get it do you?
These places have ALREADY been searched for signs of evaporites and NONE have been found. Phil Christensen has specifically searched for evaporates and carbonates in all these "obvious" areas and found none. He and his team have searched the entire planet and found NO areas of evaporite outcrop.
The conclusion? these lithologies are NOT PRESENT to any significant degree ANYWHERE on Mars.