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The depth predicted by the square root of seafloor age found by the 1974 cooling mantle derivation [4] is too deep for seafloor older than 80 million years. [5] Depth is better explained by a cooling lithosphere plate model rather than the cooling mantle half-space. [5] The plate has a constant temperature at its base and spreading edge.
The grids can be used with the Generic Mapping Tools (GMT) system. The GEBCO Digital Atlas — a two volume CDROM set which contains: The GEBCO One Minute Grid; A global set of digital bathymetric contours and coastlines; The GEBCO Gazetteer of Undersea Feature Names: a digital gazetteer of undersea feature names.
Synonyms include seafloor mapping, seabed mapping, seafloor imaging and seabed imaging. Bathymetric measurements are conducted with various methods, from depth sounding, sonar and lidar techniques, to buoys and satellite altimetry. Various methods have advantages and disadvantages and the specific method used depends upon the scale of the area ...
Bathymetric charts showcase depth using a series of lines and points at equal intervals, called depth contours or isobaths (a type of contour line). A closed shape with increasingly smaller shapes inside of it can indicate an ocean trench or a seamount, or underwater mountain, depending on whether the depths increase or decrease going inward.
A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about 2,600 meters (8,500 ft) and rises about 2,000 meters (6,600 ft) above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a divergent plate boundary. The rate of seafloor spreading ...
Depth contour lines show the shape of underwater relief. Coloured areas of the sea emphasise shallow water and dangerous underwater obstructions. Depths are measured from the chart datum, which is related to the local sea level. The chart datum varies according to the standard used by each national Hydrographic Office.
There are limitations to this technique. The distance between the sea floor and the sensor is related to the resolution of the map being created. [13] The closer the sensor is the sea floor, the higher the resolution will be and the farther away the sensor is to the sea floor, the lower the resolution will be.
Plate tectonics and the volume of mid-ocean ridges: the depth of the seafloor increases with distance to a ridge, as the oceanic lithosphere cools and thickens. The volume of ocean basins can be modeled using reconstructions of plate tectonics and using an age-depth relationship (see also Seafloor depth vs age).