Sedimentology

thumb|upright=1.2|A boat floats on the Mekong in Laos thumb|upright=1.2|South America's Amazon River (dark blue) and the rivers which flow into it (medium blue). The darker green marks the Amazon's [[drainage basin or watershed]]

Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impurities, such as a reddish or brownish colour from small amounts of iron oxide.

landform that is formed at the mouth of a river

400px|thumbnail|The Maspalomas Dunes of [[Gran Canaria, Canary Islands, Spain]]

thumb|upright=1.35|Gravel (largest fragment in this photo is about )

thumb|upright=1.35|Close view of pebbles

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thumb|Alluvium and adjacent constituents thumb|Alluvium deposits in the Gamtoos River|Gamtoos Valley in [[South Africa]] thumb|An alluvial plain in [[Red Rock Canyon State Park (California)]] thumb|Alluvial river deposits in the Amazon basin, near Autazes, AM, [[Brazil. The seasonal deposits are extremely fertile and crucial to subsistence farming in the Amazon Basin along the river banks.]] Alluvium (, ) is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes

thumb|Windrow of windblown silt, Northwest Territories, Canada|right Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel when dry, and lacks plasticity when wet. Silt can also be felt by the tongue as granular when placed on the front teeth (even when mixed with clay particles).

thumb|upright|Traditional laterite temple in Kerala thumb|upright|alt=This monument is constructed of laterite brickstones. It commemorates Buchanan who first described laterite at this site.|Monument of laterite brickstones at Angadipuram, [[Kerala, India, which commemorates where laterite was first described and discussed by Buchanan-Hamilton in 1807]]

process of wearing down or wearing away of rocks by the hard particles carried by rivers, glaciers, wind and waves

thumbnail|300px| Pine [[pollen under the microscope]] thumb|300px| A late Silurian [[sporangium bearing trilete spores. Such spores provide the earliest evidence of life on land. Green: A spore tetrad. Blue: A spore bearing a trilete mark – the Y-shaped scar. The spores are about 30–35 μm across.]]

Sedimentology encompasses the study of modern sediments such as sand, silt, and clay, and the processes that result in their formation (erosion and weathering), transport, deposition and diagenesis. Sedimentologists apply their understanding of modern processes to interpret geologic history through observations of sedimentary rocks and sedimentary structures. Sedimentology is a subdiscipline of geology.

fan- or cone-shaped deposit of sediment crossed and built up by streams

thumb|right|The Chinle Badlands at Grand Staircase–Escalante National Monument, [[Utah, United States]]

mineraloid and minor gemstone

thumb|upright=1.35|A form of diagenesis is permineralization, in which buried organisms are replaced by minerals. These [[trilobites (Lloydolithus) were replaced by pyrite during a specific type of permineralization called pyritization.]] thumb|upright=1.35|Permineralization in vertebra from Valgipes|Valgipes bucklandi

geologic event

processes due to wind activity

thumb|upright=1.02|Steeply-tilted layers of flysch on the coast of Bay of Biscay, at [[Zumaia, Basque Country, Spain]] Flysch () is a sequence of sedimentary rock layers that progress from deep-water and turbidity flow deposits to shallow-water shales and sandstones. It is deposited when a deep basin forms rapidly on the continental side of a mountain building episode. Examples are found near the North American Cordillera, the Alps, the Pyrenees and the Carpathians.

geological phenomenon when soil material that is ordinarily a solid behaves like a liquid

__NOTOC__ thumb|Nagelfluh-molasse, Speer, Appenzell Alps

regions of long-term subsidence creating space for infilling by sediments

thumb|upright=1.35|Pleistocene glacial lake varves at Sandend Bay in Scotland A varve is an annual layer of sediment or sedimentary rock.

type of sedimentary rock

geological process of areas of submerged seafloor being exposed above the sea level

thumb|upright=1.1|Coccolithophore cells are covered with protective calcified (chalk) scales called coccoliths

geological process in which sediments, soil and rocks are added to a landform or land mass

network of river channels separated by small, and often temporary, islands called braid bars

used for open channel flows

thumb|Turbidites are deposited in the deep ocean troughs below the continental shelf, or similar structures in deep lakes, by underwater avalanches which slide down the steep slopes of the continental shelf edge. When the material comes to rest in the ocean trough, it is the sand and other coarse material which settles first followed by mud and eventually the very fine particulate matter. It is this sequence of deposition that creates the Bouma sequences that characterize these rocks.

process by which soils decrease in volume

asphalt pit or asphalt lake

thumb|upright=1.15| Diluvial terraces on Katun River Altai Scabland, [[Altai Republic]] thumb|Giant current ripples in the Kuray Basin, Altai, Russia

thumb|Schematic of sediment accumulation (aggradation) in a river channel. The sediment is brown. The river is flowing on bedrock in the upper image, but because sediment was deposited over time the riverbed has risen. This has caused the house to be buried in the lower image.

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alt=Walrus |thumb|upright=1.5 |Sediment on the left tusk of a walrus. Walrus bioturbations in Arctic benthic sediments have large-scale ecosystem effects.

Aleurite is an unconsolidated sediment with a texture intermediately between sand and clay, similar to silt, with particle sizes ranging from .

structural basin that develops adjacent and parallel to a mountain belt

geological formation

thumb|Erosion on Koh Tao Island Colluvium (also colluvial material or colluvial soil; from the Latin colluvio 'jumbled') is a general name for loose, unconsolidated terrigenous sediments (diamicton) that have been deposited at the base of hillslopes by either rainwash, sheetwash, slow continuous downslope creep, or a variable combination of these processes. Colluvium is typically composed of a heterogeneous range of rock types and sediments ranging from silt to rock fragments of various sizes. This term is also used to specifically refer to sediment deposited at the base of a hillslope by unco

submarine features associated with island arcs and subduction zones

underwater current of usually rapidly moving, sediment-laden water moving down a slope

geomorphological process associated with rivers and streams

Illuvium is material displaced across a soil profile, from one layer to another one, by the action of rainwater. The removal of material from a soil layer is called eluviation. The transport of the material may be either mechanical or chemical. The process of deposition of illuvium is termed illuviation. It is a water-assisted transport in a basically vertical direction, as compared to alluviation, the horizontal running water transfer. The resulting deposits are called illuvial deposits. Cutans are a type of illuvial deposit.

orange-yellow to black coating found on exposed rock surfaces in arid environments

combination of physical, chemical and biological processes associated with the deposition of a particular type of sediment

movement of solid particles, typically by gravity and fluid entrainment

term in geology

particles in a flowing fluid that are transported along the bed

sediments derived from the erosion of rocks on land

In geology, cross-bedding, also known as cross-stratification, is layering within a stratum and at an angle to the main bedding plane. The sedimentary structures which result are roughly horizontal units composed of inclined layers. The original depositional layering is tilted, such tilting not being the result of post-depositional deformation. Cross-beds or "sets" are the groups of inclined layers, which are known as cross-strata.

type of rock body

portion of sediment uplifted by a fluid's flow in the process of sediment transportation

depositional feature of alluvium that accumulates on the inside bend of streams and rivers below the slip-off slope

thumb|right|250px|alt=This is a diagram and related photograph of soil layers from bedrock to soil.|A represents soil; B represents [[laterite, a regolith; C represents saprolite, a less-weathered regolith; beneath C is bedrock.]]

a rock larger than a pebble and smaller than a boulder

change in shape and direction of river channels over time

layering structure in sedimentary rocks usually less than 1 cm in thickness

soil sieve types