Table 2: The Organization of Sedimentary Rocks
|
Clastic (organized by grain |
256+ mm: boulders |
Conglomerate |
|
|
size) |
64-256 mm: cobbles |
|
|
|
|
4-64 mm: pebbles |
|
|
|
|
2-4 mm: granules |
Sandstone |
|
|
|
1-2 mm: course-grained sand |
|
|
|
|
¼ – 1 mm: medium-grained sand |
|
|
|
|
1/16 – ¼ mm: fine-grained sand |
|
|
|
|
1/256 – 1/16 mm: silt |
Siltstone |
|
|
|
|
1/256 mm or smaller: mud, clay |
Shale |
|
Clastic (special circumstances) |
Cemented fragments have sharp angles. |
Breccia |
|
|
|
Like sandstone, but has lots of feldspar. |
Arkose |
|
|
|
Like sandstone, but cement ads strong color. |
Ferruginous sandstone |
|
|
|
Like sandstone, but has lots of feldspar and some dark grains. |
Graywacke |
|
|
Chemical (organized by |
NaCl |
Rock Salt |
|
|
chemical formula) |
CaSO4 . 2H2O |
Rock Gypsum |
|
|
|
SiO2 |
Chert |
|
|
|
CaMg(CO3)2 |
Dolomite |
|
|
|
Various Other Minerals |
Anhydrite,
Hematite, Limonite, Goethite, some Borates, Nitrates, & Phosphates |
|
|
|
CaCO3 |
Travertine, Calcareous Tufa, (Chemical) Limestone |
|
|
Organic (organized by biological source) |
Shells of ocean animals |
(Shell) Limestone, Coquina |
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|
|
Paleozoic trees & other plants |
Lignite Coal, Bituminous Coal |
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|
|
Mainly protozoa shells |
Chalk |
|
|
|
Mud, clay, plant & animal remains |
Oil Shale |
|