allochthonyoudaoicibaDictYouDict[allochthon 词源字典]
"An allochthonous rock or mineral formation; especially a part of a faulted formation that has been displaced by tectonic forces. Contrasted with autochthon", Late 19th cent.; earliest use found in Nature: a weekly journal of science. Apparently from allo- + -chthon.[allochthon etymology, allochthon origin, 英语词源]