graywacke
or grey·wacke
Geology. a dark-gray coarse-grained wacke.
Origin of graywacke
1Words Nearby graywacke
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024
How to use graywacke in a sentence
Appropriately pronounced a "secondary graywacke slate," by Mr. Eaton.
Summary Narrative of an Exploratory Expedition to the Sources of the Mississippi River, in 1820 | Henry Rowe SchoolcraftIn the transition graywacke of the south of Scotland, the galena mines of Leadhills occur.
A Dictionary of Arts, Manufactures and Mines | Andrew UreTheir material, however, is not flint, but either graywacke or a kind of tough slate.
North American Stone Implements | Charles RauIs it primitive, or is it graywacke like Catskill Mountains?
Personal Memoirs Of A Residence Of Thirty Years With The Indian Tribes On The American Frontiers | Henry Rowe SchoolcraftI received a specimen of slaty graywacke from Lake Superior.
Personal Memoirs Of A Residence Of Thirty Years With The Indian Tribes On The American Frontiers | Henry Rowe Schoolcraft
Scientific definitions for graywacke
[ grā′wăk′, -wăk′ə ]
Any of various dark gray, coarse-grained sandstones that contain abundant feldspar and rock fragments and often have a clay-rich matrix. Graywackes are thought to originate in environments where erosion, transportation, and deposition happen so quickly that minerals and rock fragments do not have sufficient time to break down into finer constituents.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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