Killing the Glacial Golem Margrave at the bottom will open a temporary portal to the valley where Gaerlan's Citadel crashed (58.2N 47.9E). The golem with not respawn for one (??) hour, if you need to get back, there are portals in a bunker in Eastham that you will be flagged to use for one (??) hour. Originally the Essence of Enchantment was found here between the stones. You could give the Essence level 6 Creature Enchantment scrolls and in return it would teach you the corresponding level 7 spell.