On the continental slope, erosion of the ocean floor to create channels and submarine canyons can result from the rapid downslope flow of sediment gravity flows, bodies of sediment-laden water that move rapidly downslope as turbidity currents. Where erosion by turbidity currents creates oversteepened slopes it can also trigger underwater landslides and debris flows. Turbidity currents can erode channels and canyons into substrates ranging from recently deposited unconsolidated sediments to hard crystalline bedrock. [1] [2] [3] Almost all continental slopes and deep ocean basins display such channels and canyons resulting from sediment gravity flows and submarine canyons act as conduits for the transfer of sediment from the continents and shallow marine environments to the deep sea. [4] [5] [6] Turbidites, which are the sedimentary deposits resulting from turbidity currents, comprise some of the thickest and largest sedimentary sequences on earth, indicating that the associated erosional processes must also have played a prominent role in earth's history.
For the sequence stratigraphy page
These are present at a great range of scales and they arise in a number of quite different ways: for example, by fluvial incision and subaerial erosion (above sea level); submergence of nonmarine or shallow-marine sediments during transgression (flooding surfaces and drowning unconformities), in some cases with shoreface erosion (ravinement); shoreface erosion during regression; erosion in the marine environment as a result of storms, currents, or mass-wasting; and through condensation under conditions of diminished sediment supply (intervals of sediment starvation).
The main attribute shared by virtually all of these discontinuities, independent of origin and scale, is that to a first approximation they separate older deposits from younger ones. The recognition of discontinuities is therefore useful because they allow sedimentary successions to be divided into geometrical units that have time-stratigraphic and hence genetic significance."
A dozen or so common types of sedimentary basins are widely recognized and understood as distinct kinds of sedimentary basins that formed in particular ways. However, no single overall classification scheme for sedimentary basins is recognized as a standard, although several schemes have been proposed. Most classifications are based on one or more of these interrelated criteria:
[7] [8] [9] [10] [11] [12] [13] [14]
Although no one basin classification scheme has been widely adopted, several common types of sedimentary basins are widely accepted and well understood:
Sedimentary Basin Type | Associated Type of Plate Boundary | Description and Formation | Illustrated Examples | Modern, Active Examples | Ancient (No longer active) Examples |
---|---|---|---|---|---|
Rift basin | Divergent | Rift basins are elongate sedimentary basins formed in depressions created by tectonically-induced thinning (stretching) of continental crust, generally bounded by normal faults that create
grabens and
half-grabens.
[15]
[16] Some authors recognize two subtypes:
[17]
|
Terrestrial rift valleys Proto-oceanic rift troughs |
||
Passive margin | Divergent | Passive margins generally have deep sedimentary basins that form along the margin of a continent after two continents have completely rifted apart to become separated by an ocean. [21] [22] Cooling and densification of the underlying lithosphere over tens of millions of years drives subsidence that allows thick accumulations of sediments eroded from the adjacent content. [23] [24] [25] Two types are recognized, Non-volcanic passive margins and Volcanic passive margins. |
| ||
Foreland Basin | Convergent | An elongate basin that develops adjacent and parallel to an actively growing mountain belt when the immense mass created by the growing mountains causes the lithosphere to bend downward. [26] [27] | |||
Back-arc basin | Convergent | Back-arc basins result from stretching and thinning of crust behind volcanic arcs resulting when tensional forces created at the plate boundary pull the overriding plate toward the subducting oceanic plate in a process known as oceanic trench rollback. This only occurs when the subducting oceanic crust is older (>55 million years old), and therefore colder and denser, and being subducted at an angle greater than 30 degrees. [28] [29] [30] | |||
Forearc basin | Convergent |
A sedimentary basin formed in association with a convergent plate tectonic boundary in the gap between an active volcanic arc and the associated trench, thus above the subducting oceanic plate. The formation of a forearc basin is often created by the vertical growth of an accretionary prism that acts as a linear dam, parallel to the volcanic arc, creating a depression in which sediments can accumulate. [31] [32] [33] [33] |
|
||
Oceanic trench | Convergent |
Trench basins are deep linear depressions formed where a subducting oceanic plate descends into the mantle, beneath the overriding continental (Andean type) or oceanic plate (Mariana type). Trenches form in the deep ocean but, particularly where the overriding plate is continental crust they can accumulate thick sequences of sediments from eroding coastal mountains. Smaller 'trench slope basins' can form in association with a trench can form directly atop the associated accretionary prism as it grows and changes shape creating ponded basins. [39] [40] |
|
||
Pull-apart basin | Transform |
Pull-apart basins is are created along major strike-slip faults where a bend in the fault geometry or the splitting of the fault into two or more faults creates tensional forces that cause crustal thinning or stretching due to extension, creating a regional depression. [43] [44] [45] Frequently, the basins are rhombic or sigmoidal in shape. [46] |
|||
Cratonic basin (Intracratonic basin) | None |
A broad comparatively shallow basin formed far from the edge of a continental craton as a result of prolonged, broadly distributed but slow subsidence of the continental lithosphere relative to the surrounding area. They are commonly filled with shallow water marine or terrestrial sedimentary rocks. The geodynamic forces that create them remain poorly understood. [48] [49] [50] [51] [52] |
Ingersoll2011
was invoked but never defined (see the
help page).Klemme 1980
was invoked but never defined (see the
help page).AllenandAllen
was invoked but never defined (see the
help page).Selley Sonnenberg
was invoked but never defined (see the
help page).On the continental slope, erosion of the ocean floor to create channels and submarine canyons can result from the rapid downslope flow of sediment gravity flows, bodies of sediment-laden water that move rapidly downslope as turbidity currents. Where erosion by turbidity currents creates oversteepened slopes it can also trigger underwater landslides and debris flows. Turbidity currents can erode channels and canyons into substrates ranging from recently deposited unconsolidated sediments to hard crystalline bedrock. [1] [2] [3] Almost all continental slopes and deep ocean basins display such channels and canyons resulting from sediment gravity flows and submarine canyons act as conduits for the transfer of sediment from the continents and shallow marine environments to the deep sea. [4] [5] [6] Turbidites, which are the sedimentary deposits resulting from turbidity currents, comprise some of the thickest and largest sedimentary sequences on earth, indicating that the associated erosional processes must also have played a prominent role in earth's history.
For the sequence stratigraphy page
These are present at a great range of scales and they arise in a number of quite different ways: for example, by fluvial incision and subaerial erosion (above sea level); submergence of nonmarine or shallow-marine sediments during transgression (flooding surfaces and drowning unconformities), in some cases with shoreface erosion (ravinement); shoreface erosion during regression; erosion in the marine environment as a result of storms, currents, or mass-wasting; and through condensation under conditions of diminished sediment supply (intervals of sediment starvation).
The main attribute shared by virtually all of these discontinuities, independent of origin and scale, is that to a first approximation they separate older deposits from younger ones. The recognition of discontinuities is therefore useful because they allow sedimentary successions to be divided into geometrical units that have time-stratigraphic and hence genetic significance."
A dozen or so common types of sedimentary basins are widely recognized and understood as distinct kinds of sedimentary basins that formed in particular ways. However, no single overall classification scheme for sedimentary basins is recognized as a standard, although several schemes have been proposed. Most classifications are based on one or more of these interrelated criteria:
[7] [8] [9] [10] [11] [12] [13] [14]
Although no one basin classification scheme has been widely adopted, several common types of sedimentary basins are widely accepted and well understood:
Sedimentary Basin Type | Associated Type of Plate Boundary | Description and Formation | Illustrated Examples | Modern, Active Examples | Ancient (No longer active) Examples |
---|---|---|---|---|---|
Rift basin | Divergent | Rift basins are elongate sedimentary basins formed in depressions created by tectonically-induced thinning (stretching) of continental crust, generally bounded by normal faults that create
grabens and
half-grabens.
[15]
[16] Some authors recognize two subtypes:
[17]
|
Terrestrial rift valleys Proto-oceanic rift troughs |
||
Passive margin | Divergent | Passive margins generally have deep sedimentary basins that form along the margin of a continent after two continents have completely rifted apart to become separated by an ocean. [21] [22] Cooling and densification of the underlying lithosphere over tens of millions of years drives subsidence that allows thick accumulations of sediments eroded from the adjacent content. [23] [24] [25] Two types are recognized, Non-volcanic passive margins and Volcanic passive margins. |
| ||
Foreland Basin | Convergent | An elongate basin that develops adjacent and parallel to an actively growing mountain belt when the immense mass created by the growing mountains causes the lithosphere to bend downward. [26] [27] | |||
Back-arc basin | Convergent | Back-arc basins result from stretching and thinning of crust behind volcanic arcs resulting when tensional forces created at the plate boundary pull the overriding plate toward the subducting oceanic plate in a process known as oceanic trench rollback. This only occurs when the subducting oceanic crust is older (>55 million years old), and therefore colder and denser, and being subducted at an angle greater than 30 degrees. [28] [29] [30] | |||
Forearc basin | Convergent |
A sedimentary basin formed in association with a convergent plate tectonic boundary in the gap between an active volcanic arc and the associated trench, thus above the subducting oceanic plate. The formation of a forearc basin is often created by the vertical growth of an accretionary prism that acts as a linear dam, parallel to the volcanic arc, creating a depression in which sediments can accumulate. [31] [32] [33] [33] |
|
||
Oceanic trench | Convergent |
Trench basins are deep linear depressions formed where a subducting oceanic plate descends into the mantle, beneath the overriding continental (Andean type) or oceanic plate (Mariana type). Trenches form in the deep ocean but, particularly where the overriding plate is continental crust they can accumulate thick sequences of sediments from eroding coastal mountains. Smaller 'trench slope basins' can form in association with a trench can form directly atop the associated accretionary prism as it grows and changes shape creating ponded basins. [39] [40] |
|
||
Pull-apart basin | Transform |
Pull-apart basins is are created along major strike-slip faults where a bend in the fault geometry or the splitting of the fault into two or more faults creates tensional forces that cause crustal thinning or stretching due to extension, creating a regional depression. [43] [44] [45] Frequently, the basins are rhombic or sigmoidal in shape. [46] |
|||
Cratonic basin (Intracratonic basin) | None |
A broad comparatively shallow basin formed far from the edge of a continental craton as a result of prolonged, broadly distributed but slow subsidence of the continental lithosphere relative to the surrounding area. They are commonly filled with shallow water marine or terrestrial sedimentary rocks. The geodynamic forces that create them remain poorly understood. [48] [49] [50] [51] [52] |
Ingersoll2011
was invoked but never defined (see the
help page).Klemme 1980
was invoked but never defined (see the
help page).AllenandAllen
was invoked but never defined (see the
help page).Selley Sonnenberg
was invoked but never defined (see the
help page).