Glossary of Karst and Cave Terms
Younger sediment or sedimentary rock that infills pre-existing cavities, such as grikes, dolines or cave passages, in older rocks. The most common form is a fissure fill, known as a neptunian dike. Neptunian deposits occupy voids in non-karstic as well as karstic rocks, and the combination of void and fill may subsequently be buried by still younger rocks. They may thus become part of a paleokarst .