Sedimentary Petrology 03: Sedimentary rock classification - Part 1
Some of the contents on this page is outside the scope of the lecture.
- Rest (no movement)
- Saltation ("bouncing")
- Mass flow (viscous flow)
Sediment gravity flow
|Name of Rock||Sediment Type||Texture|
|Conglomerate||gravel - rounded fragments||coarse - over 2 mm|
|Breccia||gravel - angular fragments||coarse - over 2 mm|
|Sandstone||sand||medium - 1/16 to 2mm|
|Siltstone||mud||fine - 1/256 to 1/16 mm|
|Shale||mud||very fine - less than 1/256 mm|
|Name of Rock||Composition||Texture|
|Crystalline Limestone||Calcite - CaCO3||coarse to fine crystalline|
|Fossiliferous Limestone||Calcite - CaCO3||visible fragments of shells|
|Chert||Quartz - SiO2||very fine crystalline|
|Gypsum||Gypsum - CaSO3-2H2O||fine to course crystalline|
|Rock Salt||Halite - NaCl||fine to course crystalline|
|Bituinous Coal||Organic Matter||fine|
- Turbidity current
- Fluidized sedimental flow
- Grain flow
- Debris flow
Sediment support mechanism
- Upward intergranular flow
- Grain interaction
- Matrix strength
Sedimentary rock classification
Sedimentary rock is classified into two groups based on how they form. They are clastic and chemical.
Clastic sedimentary rock
Clastic sedimentary rock is formed as bits of weathered rock become cemented together. Because all kinds of rock are subject to weathering many different minerals can make up this group of rocks. Clays and quartz are the most common.
Clastic sedimentary rock classification
Classification of clastic sedimentary rocks is done according to the size of the sediments that make up the rock.
Chemical sedimentary rock
Chemical sedimentary rocks form from dissolved minerals that are precipitated or separated from water. This happens most frequently when water evaporates leaving the minerals behind.