Search results
Results from the WOW.Com Content Network
Tectonic subsidence is the sinking of the Earth's crust on a large scale, relative to crustal-scale features or the geoid. [1] The movement of crustal plates and accommodation spaces produced by faulting [2] brought about subsidence on a large scale in a variety of environments, including passive margins, aulacogens, fore-arc basins, foreland basins, intercontinental basins and pull-apart basins.
Subsidence frequently causes major problems in karst terrains, where dissolution of limestone by fluid flow in the subsurface creates voids (i.e., caves).If the roof of a void becomes too weak, it can collapse and the overlying rock and earth will fall into the space, causing subsidence at the surface.
where is the tectonically driven subsidence, is the decompacted sediment thickness, is the mean sediment density, is the average depth at which the sedimentary units were deposited, and are the densities of the water and mantle respectively, and the difference in sea-level height between the Present and the time at which the sediments were deposited.
In geology, a basin is a region where subsidence generates accommodation space for the deposition of sediments. A pull-apart basin is a structural basin where two overlapping (en echelon) strike-slip faults or a fault bend create an area of crustal extension undergoing tension, which causes the basin to sink down.
The temperature underneath the orogen is much higher and weakens the lithosphere. Thus, the thrust belt is mobile and the foreland basin system becomes deformed over time. Syntectonic unconformities demonstrate simultaneous subsidence and tectonic activity. Foreland basins are filled with sediments which erode from the adjacent mountain belt.
Tectonic map of the Mediterranean, showing the position of the Alps within other structures of the Alpide belt. The Alps form a northward convex arc around their southeastern foreland basin, the Po river basin (to be precise the south is in fact their hinterland).
Subsidence of the lithosphere acts to increase the thickness of the portion of the lowermost crust which behaves viscously. If the freezing of the asthenosphere dominates (2) the system is stable, however if subsidence, and therefore separation of the lower lithosphere dominates (3) the system is unstable.
Area of subsidence caused by the collapse of an underlying structure, such as sinkholes in karst terrain. Sink: an endorheic depression generally containing a persistent or intermittent (seasonal) lake, a salt flat (playa) or dry lake, or an ephemeral lake. Panhole: a shallow depression or basin eroded into flat or gently sloping, cohesive rock ...