(Glacial Oasis isn't a spell.)
Glacial Oasis enters the battlefield tapped.
Glacial Oasis is indestructible. (Destroy effects and lethal damage don't destroy it.)
: Add or to your mana pool.
Sacrifice Glacial Oasis: Add or to your mana pool.
: Add 
or 
to your mana pool. or to your mana pool.
