dyke-rock

plural dyke-rocks

1. geographyA type of igneous rock that fills a dyke (a rock filling a fissure that is now often rising above the older stratum that has eroded away).

   Appears to be a fine-grained dioritic dyke rock, but is too dirty and stained to be satisfactorily examined.

   1901, Smithsonian Institution, Board of Regents, Annual Report of the Board of Regents of the Smithsonian Institution, page 427

   2 more examples

   If the dyke is of great thickness the centre may be coarsely crystalline as a deep-seated plutonic rock and this makes it difficult to distinguish a dyke rock in hand specimen.

   1983, B. Simpson, Rock & Minerals, page 88

   As a dyke is made of igneous rock, it is usually possible to date it by radiometric dating methods, which give an absolute age for the dyke rock.

   2017, Chris Pellant, Helen Pellant, Geological Structures - An Introductory Field Guide, page 14