I know that Durantium are tied to asteroids which can vary depending on setting.
Antimatter ONLY found at black holes which also varies on settings.
Elerium ONLY spawns in Nebulae which again are dependent on galaxy-wide settings.
When you set your resources to LOW you are lowering the percentage on each node the would normally be found.
If you eliminate or set to RARE the nodes: Black Holes, Asteroids, Nebulae and also set resources to ZERO you 'should' potentially eliminate most resources.
It would helpful to new players to have a tool tip to describe this but Ill see about putting the information on the Wikia.