Classifying Clastic Sedimentary Rocks
There are eight major types of clastic sedimentary rocks:
| Rock | Sediment | Texture |
Composition | Environment |
|---|---|---|---|---|
| Shale | Silts and clays | Silts and clays | Microscopic silica & clay minerals | Quiet waters (lakes, deep marine) |
| Sandstone | Sand | Sand | Quartz, feldspars, & lithic fragments | Moderate engery environments (rivers, beaches) |
| Sandstone: Quartz arenite |
Sand | Sand | Quartz | Beaches, deserts |
| Sandstone: Arkose | Sand | Sand | Quartz & abundant feldspars | Dry environments (Deserts) |
| Sandstone: Lithic sandstone |
Sand | Sand | Quartz, feldspars, rock fragments | Alluvial fans, deserts |
| Sandstone: Wacke | Sand | Sand | Quartz, feldspars, rock fragments, > than 15% mud | Mubmarine avalanches or turbidity currents |
| Conglomerate | Rounded particles > 2 mm | Gravels through boulders | rock fragments of varying sizes, with sand to clay 'binding' them together | Indicates processing by transport; Deposited away from source area (rivers) |
| Breccia | Angular particles > 2 mm | Gravels through boulders | rock fragments of varying sizes, with sand to clay 'binding' them together | Indicates lack of transport processing. Deposited close to source (alluvial fans) |