DictionarydikeRock sheet
noun

dike

A sheet of igneous rock cutting across surrounding rock layers.

A dark dike cuts across the pale rock layers.

Etymology

Old English dīc could name a ditch or raised earthwork. Geology borrows the embankment’s wall-like image for a sheet of rock that cuts across surrounding formations.

More examples

  • The geologist traces the dike up the cliff.
  • The diagram shows magma cooling inside the dike.
  • Several narrow dikes intersect the older rock.

Forms

dike · dikes

Similar words

intrusion
The broader geological category of rock formed from magma entering older rock.
sill
A sill lies parallel to existing rock layers; a dike cuts across them.