Also found in: Acronyms, Encyclopedia, Wikipedia.


 (grā′wăk′, -wăk′ə)
Any of various dark gray sandstones that contain shale.

[Partial translation of German Grauwacke : grau, gray + Wacke, rock (from Middle High German, from Old High German waggo, boulder; see wegh- in Indo-European roots).]
References in periodicals archive ?
9 scales the spontaneous imbibition of water into different porous media (Berea, chalk, and Graywacke cores) with different initial water saturations.
9 and 18 successfully scaled their spontaneous imbibition water-air experiments in sandstone, chalk, and Graywacke rock samples.
The property is dominated by Jurassic Laberge group argillite, graywacke, siltstone, limestone and conglomerate, which are underlain by Triassic Stuhini group volcanics and carbonate.