Organic Sediments
Clastic Sediments
Outline
Chemical sedimentary rocks are classified according to the predominant minerals precipitated to form the rock and their texture. The are deposited by precipitation from solution rather than release from suspension.
| TEXTURE | COMPOSITION | ROCK NAME |
|---|---|---|
| Clastic | Calcite fragments and calcite cement. White or grey or blueish in colour. Fizzes stongly with dilute HCl. | LIMESTONE |
| Clastic | Rounded calcite ooliths and calcite cement. Can be dolomitized. | OOLITIC LIMESTONE |
| Clastic | Calcite fragments and calcite cement with significant alteration to the magnesium bearing carbonate dolomite. Fizzes with dilute HCl. | DOLOMITIC LIMESTONE |
| Clastic | Carbonate almost completely transformed to dolomite. Often yellowish or pinkish in colour. Fizzes weakly with dilute HCl. | DOLOMITE or DOLOSTONE |
| Crystalline | Halite, interlocking cubic crystals. | ROCK SALT |
| Crystalline | Halite with sylvite, interlocking cubic crystals, sometimes contains orange-to-red carnallite crystals. | POTASH |
| Crystalline | Gypsum, commonly interlocking prismatic or fibrous crystals. Usually white or light grey. | ROCK GYPSUM |
The table lists some of the more common chemical sediments. There are a large number of rare crystalline chemical sediments that form rocks of economic significance.
Organic Sediments
Clastic Sediments
Outline