Clastic sedimentary rocks:
* Shale: Formed from fine-grained clay and silt particles. It's often layered and breaks into thin sheets.
* Sandstone: Formed from sand-sized particles of quartz, feldspar, and other minerals. It can vary in color and texture depending on the minerals present.
* Conglomerate: Formed from rounded gravel-sized particles. The pebbles are often cemented together by a finer-grained matrix.
* Breccia: Similar to conglomerate, but with angular fragments. This indicates rapid deposition or transportation.
Chemical sedimentary rocks:
* Limestone: Formed from the accumulation of calcium carbonate shells and skeletons of marine organisms. It can be fossiliferous and often has a light color.
* Chert: Formed from the accumulation of silica (SiO2). It can be found as nodules within other rocks or as layers.
* Evaporites: Formed from the evaporation of water in shallow lakes or lagoons. Examples include halite (rock salt) and gypsum.
Organic sedimentary rocks:
* Coal: Formed from the accumulation and compaction of plant matter in swamps and bogs. It's a significant energy source.
The specific type of sedimentary rock formed depends on the following factors:
* Source of sediment: The minerals and composition of the sediment determine the type of rock formed.
* Environment of deposition: The conditions of the lake or ocean floor, such as water depth, currents, and biological activity, influence the types and sizes of sediments that accumulate.
* Diagenesis: The processes that occur after deposition, such as compaction, cementation, and recrystallization, modify the sediment and ultimately form the rock.
Therefore, a wide variety of sedimentary rocks can be formed from sediments deposited in lakes and oceans, each with its own unique characteristics and formation history.
