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An argillaceous sandstone characterized by an abundance of unstable mineral and rock fragments and a fine-grained clay matrix binding the larger, sand-size detrital fragments.



a rock of sedimentary origin consisting of small fragments (grains) of sedimentary and chiefly metamorphic and igneous rock with an admixture of fragments of basic volcanic rock and tufogenic material. A significant quantity of cementing material is characteristic. The color is usually dark gray, black, or dark green (owing to the chlorite in the cement). The fragmentary grains in the graywacke are angular or slightly rounded and are poorly sorted. Graywackes are typical for geosynclinal areas where they form thick strata originating during periods of the rapid accumulation of disintegration products from internal uplifts composed of more ancient rock.

References in periodicals archive ?
According to the Herron's (1988) classification scheme the sandstone samples plot inside the shale/wacke field close to Fe-shale field while in the Pettijohn's (1987) scheme the samples fall on the boundary between greywacke and litharenite field.
It was found that the Indus bed material used in the construction of Tarbela Dam contained slow reactive aggregates like greywacke and cryptocrystalline silica, which caused ASR (Majid et al.
Greywacke Marlborough Wild Sauvignon 2014 is an excellent savoury herbal white made with his favoured wild yeasts.
Balasubramaniam, "Large-scale triaxial testing of greywacke rockfill," Geotechnique, vol.
They included Kevin Judd, of Marlborough winemakers Cloudy Bay and Greywacke vineyard-fame in New Zealand.
Gold mineralization within the Neoproterozoic Schist Greywacke Complex (SGC) which is the largest domain in the CIZ is mainly presented by quartz veins with complex sulphide deposition: frequently massive stibnite (Mari Rosa deposit), Fe-As sulphides, W minerals and more rarely Cu-Pb-Zn sulphides (Sarzedas and Pomar deposits) (Murphy and Roberts, 1997; Shepherd, 1993).
vineyard The vineyard block used in this study has Boomer-Forward-Felta rocky loam soils on 30% to 50% slopes underlain by Franciscan melange (includes greywacke, chert, serpentinite and greenstone).
2003) classified the Siwalik sandstones of Central Nepal into sublitharenite, subarkose, lithic arenite, arkosic arenite and feldspathic greywacke.
Roderick Impey Murchison, a renowned 19thcentury geologist and one of the founding members of the Royal Geographical Society (and, for a number of years, its president), came to the area to study the greywacke or 'transition' rocks that lie under the local red sandstone.
The track in Bahrain on which the 22 drivers will compete on is made up of crushed rock A[degrees] called Greywacke aggregate A[degrees] from a quarry in Shropshire, no less.
The major reactive species are slate/phyllite, greywacke, schist/gneiss and quartzite having microcrystalline and strained quartz.