A sandstone of which the mud matrix in which the grains are embedded amounts to between 15 and 75 percent of the mass.‘The rounded conglomerate pebbles consist of siltstone, mudstone, wacke, granophyric igneous rocks, and various intermediate to felsic volcanic rocks, set in a matrix rich in quartz and feldspar grains.’
- ‘The Annascaul Formation is at least 500 m thick, and is dominated by mudrocks with subordinate quartz wacke sandstones, tuffaceous fine conglomerates and melange.’
- ‘The upper 300 m of the Haengefjeldet Formation is made up of 3-10 m thick well-sorted, normally graded, matrix-supported sandstones and wackes.’
- ‘In the Western zone and the contiguous Hooper Complex, turbiditic quartz wacke was deposited on the Kimberley Craton between c. 1872 and 1865 Ma.’
- ‘Greywacke is an old term still sometimes used for a particular type of wacke especially in grey-coloured turbidite sequences.’
Early 19th century from German, from Middle High German wacke ‘large stone’, Old High German wacko ‘pebble’.
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