Formation and Classification of Sedimentary Rocks

This set of flashcards contains terminology and definitions related to the formation and classification of sedimentary rocks, including types of sediments and the processes involved in forming sedimentary rock.

Sediments

Naturally occurring unconsolidated material consisting of loose fragments of bedrock, minerals, shells, and crystals that precipitate from water.

Diagenesis

The process through which sediments become consolidated into sedimentary rock.

Compaction

The process of pressure squeezing sediments closer together to eliminate water.

Cementation

The process where minerals bind sediments together as they undergo compaction.

Lithification

The process of turning sediments into solid rock.

Detrital (clastic) rocks

Sedimentary rocks composed of sediments derived from weathered rocks.

Conglomerate

A type of clastic rock made of rounded pebbles.

Breccia

A type of clastic rock consisting of angular rubble fragments.

Sandstone

A clastic rock where the grains are smaller than two millimeters but larger than 0.06 millimeters.

Shale

A mudstone with well-defined thin layers that split easily.

Arcos sandstone

Quartzenstone with more than 25% potassium feldspar, indicating less weathering.

Lithic sandstone

Sandstone that contains rock fragments and is usually poorly sorted.

Quartz sandstone

Sandstone primarily composed of quartz, indicating extensive weathering.

Graywacke

A type of sandstone composed of more than 15% fine-grained matrix, indicating a high mud content.

Carbonates

Rocks that contain the carbonate anion (CO3) and are typically composed of calcite or dolomite.

Limestone

A carbonate rock made primarily of calcite.

Dolostone

A carbonate rock made primarily of dolomite.

Evaporates

Chemical sedimentary rocks formed from the precipitation of salts, commonly from seawater.

Chert

Sedimentary rock made of microcrystalline quartz that can be either chemical or biochemical in origin.

Coal

An organic sedimentary rock formed from the remains of plants in anoxic environments.

Anoxic environment

A condition where there is little to no oxygen, essential for coal formation.