((That wouldn't really be out of line with faery mythology. A bit more malicious than mischievous, but it still works. Might even be specific to the fae of that area.))
Rumors, some substantiated, place tribes of fae at many such locations around the world. One common element of these stories is their particular aptitude for a strange variety of naturalistic magic; this is typically attributed to close association with local elementals over the course of many generations. Accounts of their intelligence vary, but even the least generous attribute a sort of playfulness beyond the standard of animal minds.
((What I'm getting at here are things like foxfire/marsh lightning, unnaturally active plant growth, working of non-ferrous metals without fire, hoarfrost, etc.--with different groups of fae possessing different aptitudes related to the sort of elemental they're connected to.))
((Holy crap I didn't realize how huge the chasm could get until I google searched 3000 km. That's the vertical length of Australia!))
((Yeah, it's... really honkin' big. Though if it helps, the mental image I have of it is more of a sawtoothed thing, as opposed to the Grand Canyon writ large. So the points where the two edges have been connected are places where a "tooth" on each side (themselves many square kilometers of land) happened to align, while the widest point is near the center of the rift, where two "gaps" aligned". AKA there are signs of violence in its formation, rather than gradual erosion.))