Greywackes are mostly grey, brown, yellow, or black, dull-colored sandy rocks that may occur in thick or thin beds along with shales and limestones. Some varieties include feldspathic greywacke, rich in feldspar, and lithic greywacke, rich in other tiny rock fragments.

2023年4月23日 · Graywacke sandstone is a sedimentary rock that is made up mosttly of sand-size grains that were rapidly deposited very near the source rock grom which they were weathered.

2015年2月28日 · Graywacke sandstone is a sedimentary rock that is made up mostly of sand-size grains that were rapidly deposited very near the source rock from which they were weathered.

2025年2月25日 · Sedimentary rock - Wackes, Stratification, Deposition: Wacke, or graywacke, is the name applied to generally dark-coloured, very strongly bonded sandstones that consist of a heterogeneous mixture of rock fragments, feldspar, and quartz of sand size, together with appreciable amounts of mud matrix.

2015年2月28日 · Graywacke sandstone is the product of underwater landslides that carry sand, silt, rock fragments, and plant and animal debris off of the continental margin and rapidly deposit them in deep ocean environments.

Graywacke is a variety of impure sandstones and is generally characterized by its hardness, dark color, and poorly sorted angular grains of quartz, feldspar, and small rock of lithic fragments set in a compact fine clay and muddy matrix (Figs 5.26 (B), 5.31 and 5.32).

Graywacke is abundant within the sedimentary section, esp. in the older strata, usually occurring as thick, extensive bodies with sole marks of various kinds and exhibiting massive or obscure stratification in the thicker units but marked graded bedding in the thinner layers.

2016年8月12日 · Greywacke (pronounced “grey-wacky”) is a drab, grey stone—technically, a sedimentary rock–made up of layers of very hard, clay-based, muddy grey sandstone criss-crossed through with layers of argillite (a type of mudstone) and grains of quartz, feldspar, and other small rock and mineral fragments.

Graywacke rock is a type of sedimentary rock, which is also known as immature sandstone, which is indurated, dark grey and consisting of poorly sorted angular to sub-angular, sand-sized grains.

Greywacke is a term with conflicting definitions, referring to either sandstone with a muddy matrix or sandstone with many lithic fragments (small rock pieces). Figure 5.33: The Rochester Shale, New York.