graywacke

/gray"wak', -wak'euh/, n.
Geol. a dark-gray coarse-grained wacke.
Also, greywacke.
[1805-15; partly trans., partly adapted from G Grauwache; see WACKE]

* * *

or dirty sandstone

Sedimentary rock composed of sand-sized grains in a fine-grained clay matrix.

The sand-sized grains frequently include rock fragments of wide-ranging mineralogies (e.g., pyroxenes, amphiboles, feldspars, and quartz). The clay matrix may constitute up to 50% of the volume. Of the clay minerals, chlorite and biotite are most abundant. The matrix tends to bind the grains strongly and form a relatively hard rock.

* * *


Universalium. 2010.

Look at other dictionaries:

  • Graywacke — Gray wacke , n. [G. grauwacke; grau gray + wacke wacke. See {Gray}, and {Wacke}, and cf. {Grauwacke}.] (Geol.) A conglomerate or grit rock, consisting of rounded pebbles and sand firmly united together. [1913 Webster] Note: This term, derived… …   The Collaborative International Dictionary of English

  • graywacke — [grā′wak΄] n. [partial transl. of Ger grauwacke: see GRAY1 &] 1. a nonporous, dark colored sandstone containing angular particles of other rocks 2. a fine grained conglomerate resembling sandstone …   English World dictionary

  • graywacke — noun Etymology: partial translation of German Grauwacke Date: 1811 a coarse usually dark gray sandstone or fine grained conglomerate composed of firmly cemented fragments (as of quartz or feldspar) …   New Collegiate Dictionary

  • graywacke — n. (Geology) coarse grained wacke of dark gray color …   English contemporary dictionary

  • graywacke — noun US spelling of greywacke …   English new terms dictionary

  • graywacke — gray·wacke …   English syllables

  • graywacke — US var. of GREYWACKE …   Useful english dictionary

  • Jeannette Island — ( ru. Остров Жаннетты, Ostrov Zhannetty ) is the easternmost island of the De Long Islands archipelago in the East Siberian Sea. It is the second smallest island of the De Long group, being only 2km in length. It has an area of approximately… …   Wikipedia

  • San Bruno Mountain — Infobox Mountain Name = San Bruno Mountain Photo = San Bruno Mountain.jpg Photo size = 300px Caption = San Bruno Mountain, from Daly City pushpin pushpin label position = right pushpin map caption = Location of San Bruno Mountain in California… …   Wikipedia

  • flysch — /flish/, n. Geol. an association of certain types of marine sedimentary rocks characteristic of deposition in a foredeep. [1845 55; < G < Swiss G flisch referring to such deposits in the Swiss Alps; perh. akin to Swabian dial. flins slate (akin… …   Universalium

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.