Erosion and tectonics
Encyclopedia
The interplay between erosion and tectonics has been a matter of debate since the early 1990s. While tectonic effects
on surface processes such as erosion
(for example, the river entrainment subsequent to a tectonic rock uplift) have been long recognized, the reverse (the effects of erosion on tectonic deformation) has only recently been addressed thanks to the availability of computer modelling techniques.
Tectonics modify erosion because it modifies the surface topography
, which is the most important parameter controlling surface processes of mass transport. Erosion might be reduced on a flat landscape before a normal fault generates a topographic gradient for example. Landforms are generally considered as the result of the interaction between the tectonic and isostatic uplift and the response of surface erosion.
The way the tectonic deformation is influenced by erosion is more subtle and is produced by the weight of the mass removed (eroded) from the surface and the weight of the deposited sediments, which in some circumstances can become relevant enough as to modify the state of stress at depth and the pattern of tectonic deformation.
Although originally proposed for continental collision
settings, presently the effects of erosion on tectonic deformation have been extended to a diversity of tectonic settings including continental margin
s, plate subduction
, and high plateaus.
Tectonics
Tectonics is a field of study within geology concerned generally with the structures within the lithosphere of the Earth and particularly with the forces and movements that have operated in a region to create these structures.Tectonics is concerned with the orogenies and tectonic development of...
on surface processes such as erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
(for example, the river entrainment subsequent to a tectonic rock uplift) have been long recognized, the reverse (the effects of erosion on tectonic deformation) has only recently been addressed thanks to the availability of computer modelling techniques.
Tectonics modify erosion because it modifies the surface topography
Topography
Topography is the study of Earth's surface shape and features or those ofplanets, moons, and asteroids...
, which is the most important parameter controlling surface processes of mass transport. Erosion might be reduced on a flat landscape before a normal fault generates a topographic gradient for example. Landforms are generally considered as the result of the interaction between the tectonic and isostatic uplift and the response of surface erosion.
The way the tectonic deformation is influenced by erosion is more subtle and is produced by the weight of the mass removed (eroded) from the surface and the weight of the deposited sediments, which in some circumstances can become relevant enough as to modify the state of stress at depth and the pattern of tectonic deformation.
Although originally proposed for continental collision
Continental collision
Continental collision is a phenomenon of the plate tectonics of Earth that occurs at convergent boundaries. Continental collision is a variation on the fundamental process of subduction, whereby the subduction zone is destroyed, mountains produced, and two continents sutured together...
settings, presently the effects of erosion on tectonic deformation have been extended to a diversity of tectonic settings including continental margin
Continental margin
The continental margin is the zone of the ocean floor that separates the thin oceanic crust from thick continental crust. Continental margins constitute about 28% of the oceanic area....
s, plate subduction
Subduction
In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. These 3D regions of mantle downwellings are known as "Subduction Zones"...
, and high plateaus.