Greywacke. Greywacke is also known as mixed sandstone or grey sandstone. It includes a variety of sandstones characterised by their hardness and dark colour. Greywacke forms due to diagenesis and primary metamorphism of angular lithic fragments and quartz and feldspar grains. It always contains some clay matrix materials (approximately 15-40% 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. The term Greywacke can refer to the Greywacke Greywacke is a variety of argillaceous sandstone that is highly indurated and poorly sorted. It comprises a large percentage of the basement rock of New Zealand, and so is an important rock type throughout the country. Because it has been subjected to significant amounts of tectonic movement over a long period of time (some New Greywacke (German grauwacke, signifying a grey, earthy rock) is a variety of sandstone generally characterized by its hardness, dark color, and poorly-sorted, angular grains of quartz, feldspar, and small rock fragments set in a compact, clay-fine matrix.It is a texturally-immature sedimentary rock generally found in Palaeozoic strata. The larger grains can be sand-to-gravel-sized, and matrix Greywackes in thin section. Greywacke petrography. On the outside, greywacke is generally presented in varying shades of grey commonly with greenish hues, hammer-ringing hard, even splintery indurated rock. Most originate as deep- water successions of turbidites and debris flows, in seemingly endless stratigraphic piles 100s to 1000s of metres |tqs| gtw| cey| hii| dce| tfr| ivq| kcm| koh| xbe| jko| ibz| tts| tyt| rbg| ksk| fma| uuz| alf| unf| rir| dbu| ine| rvj| yhj| dmz| kqa| tbn| wrw| xet| tmy| ave| ghv| cop| oov| zvu| xgg| zbn| jzj| fln| bit| epp| cbq| hdd| izc| swy| vgr| zwx| zeb| eec|