The definition of allochtohonous is a geological term that is rocks that are found in a region that differs from where they were formed.
An example of allochthonous rock is till, which is found under, or deposited by, a glacier.
originating elsewhere; not native to a place
Origin of allochthonousallo- + (auto)chthon + -ous
- Originating or formed in a place other than where found: allochthonous rocks; an allochthonous population.
- Ecology Not indigenous: an allochthonous organism.
Ancient Greek ἄλλος (allos, “other”) + χθών (khthōn, “earth, ground”)