Originating in a place other than where it is found.(adjective)
Buried or found in a place remote from the site of formation.(adjective)
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Use "allochthonous" in a sentence
"More generally, given that the magnitude and recurrence interval of water levels produced by ice jams often exceed those of open-water conditions, breakup is probably the main supplier of allochthonous organic material in cold-regions rivers ."
"The two methodologies give opposite results when accounting for the input of allochthonous (produced outside) organic matter to a particular ecosystem: CO2 flux measurement gives negative NEP due to increased CO2 emission from soil to atmosphere, while weighing gives a higher accumulation of organic carbon (C) in the soil."
"In terms of flora, the most affected is San Félix island, with 42% of allochthonous plants."