Sedimentary rock

Sedimentary rocks are types of rock that are formed by the accumulation or deposition of small particles and subsequent cementation of mineral or organic particles on the floor of oceans or other bodies of water at the Earth's surface.

Rocks are usually grouped into three main groups: igneous rocks, metamorphic rocks and sedimentary rocks.

Sedimentary rocks are only a thin veneer over a crust consisting mainly of igneous and metamorphic rocks.

Igneous rock (derived from the Latin word ignis meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic.

Sedimentary rocks are only a thin veneer over a crust consisting mainly of igneous and metamorphic rocks.

The protolith may be a sedimentary, igneous, or existing metamorphic rock.

Sedimentary rocks are deposited in layers as strata, forming a structure called bedding.

Beds are the layers of sedimentary rocks that are distinctly different from overlying and underlying subsequent beds of different sedimentary rocks.

Sedimentary rocks are also important sources of natural resources like coal, fossil fuels, drinking water or ores.

Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams.

The particles that form a sedimentary rock are called sediment, and may be composed of geological detritus (minerals) or biological detritus (organic matter).

If buried, they may eventually become sandstone and siltstone (sedimentary rocks) through lithification.

Sedimentary rocks are deposited in layers as strata, forming a structure called bedding.

In geology and related fields, a stratum (plural: strata) is a layer of sedimentary rock or soil, or igneous rock that were formed at the Earth's surface, with internally consistent characteristics that distinguish it from other layers.

The scientific discipline that studies the properties and origin of sedimentary rocks is called sedimentology.

Sedimentologists apply their understanding of modern processes to interpret geologic history through observations of sedimentary rocks and sedimentary structures.

Sedimentology is part of both geology and physical geography and overlaps partly with other disciplines in the Earth sciences, such as pedology, geomorphology, geochemistry and structural geology.

There are three major types of rock: igneous, sedimentary, and metamorphic.

The classification of clastic sedimentary rocks parallels this scheme; conglomerates and breccias are made mostly of gravel, sandstones are made mostly of sand, and mudrocks are made mostly of the finest material.

Conglomerate is a coarse-grained clastic sedimentary rock that is composed of a substantial fraction of rounded to subangular gravel-size clasts, e.g., granules, pebbles, cobbles, and boulders, larger than 2 mm in diameter.

The classification of clastic sedimentary rocks parallels this scheme; conglomerates and breccias are made mostly of gravel, sandstones are made mostly of sand, and mudrocks are made mostly of the finest material.

A mudstone is a siliciclastic sedimentary rock that contains a mixture of silt- and clay-sized particles (at least 1/3 of each).

The classification of clastic sedimentary rocks parallels this scheme; conglomerates and breccias are made mostly of gravel, sandstones are made mostly of sand, and mudrocks are made mostly of the finest material.

A breccia may have a variety of different origins, as indicated by the named types including sedimentary breccia, tectonic breccia, igneous breccia, impact breccia, and hydrothermal breccia.

This tripartite subdivision is mirrored by the broad categories of rudites, arenites, and lutites, respectively, in older literature.

Rudite is a general name used for a sedimentary rocks that are composed of rounded or angular detrital grains, i.e. granules, pebbles, cobbles, and boulders, which are coarser than sand in size.

Most geologists use the Udden-Wentworth grain size scale and divide unconsolidated sediment into three fractions: gravel (>2 mm diameter), sand (1/16 to 2 mm diameter), and mud (clay is

Ancient mud deposits harden over geological time to form sedimentary rock such as shale or mudstone (generally called lutites).

In carbonate based rocks such as limestone or chalk, chert or flint concretions are common, while terrestrial sandstones can have iron concretions.

Limestone is a carbonate sedimentary rock that is often composed of the skeletal fragments of marine organisms such as coral, foraminifera, and molluscs.

Most authors use "shale" as a term for a fissile mudrock (regardless of grain size) although some older literature uses the term "shale" as a synonym for mudrock.

Shale is a fine-grained, clastic sedimentary rock, composed of mud that is a mix of flakes of clay minerals and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite.

This tripartite subdivision is mirrored by the broad categories of rudites, arenites, and lutites, respectively, in older literature.

Lutite is old terminology, which is not widely used, by Earth scientists in field descriptions for fine-grained, sedimentary rocks, which are composed of silt-size sediment, clay-size sediment, or a mixture of both.

In carbonate based rocks such as limestone or chalk, chert or flint concretions are common, while terrestrial sandstones can have iron concretions. The most common minerals involved in permineralization are cements of carbonates (especially calcite), forms of amorphous silica (chalcedony, flint, chert) and pyrite.

Chert is a hard, fine-grained sedimentary rock composed of crystals of quartz (silica) that are very small (microcrystalline or cryptocrystalline).

This tripartite subdivision is mirrored by the broad categories of rudites, arenites, and lutites, respectively, in older literature.

Arenite (Latin: Arena, "sand") is a sedimentary clastic rock with sand grain size between 0.0625 mm (0.00246 in) and 2 mm (0.08 in) and contain less than 15% matrix.

Although the Dott classification scheme is widely used by sedimentologists, common names like greywacke, arkose, and quartz sandstone are still widely used by non-specialists and in popular literature.

Arkose is a detrital sedimentary rock, specifically a type of sandstone containing at least 25% feldspar.

Before being deposited, the geological detritus was formed by weathering and erosion from the source area, and then transported to the place of deposition by water, wind, ice, mass movement or glaciers, which are called agents of denudation.

Deposition of transported sediment forms many types of sedimentary rocks, which make up the geologic record of Earth history.

Common chemical sedimentary rocks include oolitic limestone and rocks composed of evaporite minerals, such as halite (rock salt), sylvite, baryte and gypsum.

Oolite or oölite (egg stone) is a sedimentary rock formed from ooids, spherical grains composed of concentric layers.

Although the Dott classification scheme is widely used by sedimentologists, common names like greywacke, arkose, and quartz sandstone are still widely used by non-specialists and in popular literature.

It is a texturally immature sedimentary rock generally found in Paleozoic strata.

Most authors use "shale" as a term for a fissile mudrock (regardless of grain size) although some older literature uses the term "shale" as a synonym for mudrock.

These planes of weakness are oriented parallel to stratification in sedimentary rocks.

Common chemical sedimentary rocks include oolitic limestone and rocks composed of evaporite minerals, such as halite (rock salt), sylvite, baryte and gypsum.

Evaporite is the term for a water-soluble mineral sediment that results from concentration and crystallization by evaporation from an aqueous solution.