Just curious if there is any lore that provides either 100% proof of the possibility or the impossibility of poison or earth based destruction magic.
Is it even possible?
(I've always l edge idea of earth or poison based destruction magic)

In Morrowind there was poison based destruction magic, however there were plenty of races that could resist it, a lot of mobs resisted/immune to it, and it had the most magicka cost of any destruction spell.

Earth-based magic hasn't really been explored much at all.