lapilli

views updated May 08 2018

lapilli Pyroclastic fragments or tephra ranging in size from 2 to 64 mm. Lapilli may be composed of primary magmatic material (e.g. pumice), accessory lithic material, accidental lithic material, or accretions of wet ash-size material (accretionary lapilli). The size-term ‘lapilli’ is usually applied to the lithological clast type to give descriptive terms, e.g. ‘pumice lapilli’ or ‘accessory lithic lapilli’.

lapilli

views updated May 29 2018

lapilli fragments of stone from a volcano. XVIII. —pl. of It. lapillo— L. lapillus, dim. of lapis stone.