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Sediment is a solid material that is transported to a new location where it is deposited. [1] It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles.
The rate of sedimentation is the thickness of sediment accumulated per unit time. [8] For suspended load, this can be expressed mathematically by the Exner equation. [9] Rates of sedimentation vary from less than 3 millimeters (0.12 in) per thousand years for pelagic sediment to several meters per thousand years in portions of major river deltas.
Uluru (Ayers Rock) is a large sandstone formation in Northern Territory, Australia.. Sedimentary rocks can be subdivided into four groups based on the processes responsible for their formation: clastic sedimentary rocks, biochemical (biogenic) sedimentary rocks, chemical sedimentary rocks, and a fourth category for "other" sedimentary rocks formed by impacts, volcanism, and other minor processes.
This occurs when the forces responsible for sediment transportation are no longer sufficient to overcome the forces of gravity and friction, creating a resistance to motion; this is known as the null-point hypothesis. Deposition can also refer to the buildup of sediment from organically derived matter or chemical processes.
Folding in sediments is analysed with the principle of original horizontality, which states that sediments are deposited at their angle of repose which, for most types of sediment, is essentially horizontal. Thus, when the younging direction is known, the rocks can be "unfolded" and interpreted according to the contained sedimentary information.
A varve is an annual layer of sediment or sedimentary rock. The word 'varve' derives from the Swedish word varv whose meanings and connotations include 'revolution', 'in layers', and 'circle'. Of the many rhythmites in the geological record, varves are one of the most important and illuminating in studies of past climate change.
Soft sediment deformation (possibly a seismite) in Dead Sea sediments, Israel. Soft-sediment deformation structures or SSD, is a consequence of the loading of wet sediment as burial continues after deposition. The heavier sediment "squeezes" the water out of the underlying sediment due to its own weight. There are three common variants of SSD:
Conversely, an immature sediment contains more angular grains, diverse grain sizes, and is compositionally diverse. [1] As the sediment is transported, the unstable minerals are abraded or dissolved to leave more stable minerals, such as quartz. Mature sediments, which contain stable minerals, generally have a smaller variety of minerals than ...