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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.
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.
This example includes major erosional surface (sequence boundary) resulting from erosion and fill of a large submarine canyon. All of these perspectives on the history of a particular region are based on the study of a large three-dimensional body of sedimentary rocks that resulted from the fill of one or more sedimentary basins over time.
Techniques used to study surficial sedimentary rocks include: measuring stratigraphic sections, identifying sedimentary depositional environments and constructing a geologic map. [ 3 ] An important tool in sedimentary basin analysis is sequence stratigraphy , in which various sedimentary sequences are related to pervasive changes in sea level ...
Examples of such islands are found in the Pacific, notably the three phosphate islets of Nauru, Makatea, and Banaba, as well as Maré and Lifou in New Caledonia; Fatu Huku in the Marquesas Islands; and Henderson Island in the Pitcairn Islands. The uplift of these islands is the result of the movement of oceanic tectonic plates.
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.
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.
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 ...