crystosphene

noun
crys·​to·​sphene | \ ˈkristəˌsfēn\
plural -s

Definition of crystosphene

: a buried sheet of ice under the tundra of northern America formed by the freezing of spring water which rises from the rock beneath alluvial deposits or under swamps and spreads laterally at the zone of freezing

History and Etymology for crystosphene

cryst- (irregular from Greek krystallos ice) + -o- + Greek sphēn wedge

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