Search results
Results from the WOW.Com Content Network
Seafloor spreading. Age of oceanic lithosphere; youngest (light colour) is along spreading centers. Seafloor spreading, or seafloor spread, is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge.
Harry Hess proposed the seafloor spreading hypothesis in 1960 (published in 1962 [1]); the term "spreading of the seafloor" was introduced by geophysicist Robert S. Dietz in 1961. [2] According to Hess, seafloor was created at mid-oceanic ridges by the convection of the Earth's mantle, pushing and spreading the older crust away from the ridge. [3]
In 2020 scientists created what may be the first scientific estimate of how much microplastic currently resides in Earth's seafloor, after investigating six areas of ~3 km depth ~300 km off the Australian coast. They found the highly variable microplastic counts to be proportionate to plastic on the surface and the angle of the seafloor slope.
A profound consequence of seafloor spreading is that new crust was, and still is, being continually created along the oceanic ridges. For this reason, Heezen initially advocated the so-called "expanding Earth" hypothesis of S. Warren Carey (see above). Therefore, the question remained as to how new crust could continuously be added along the ...
A seafloor map captured by NASA. Bathymetry (/ bəˈθɪmətri /; from Ancient Greek βαθύς (bathús) 'deep' and μέτρον (métron) 'measure') [1][2] is the study of underwater depth of ocean floors (seabed topography), lake floors, or river floors. In other words, bathymetry is the underwater equivalent to hypsometry or topography.
Oceanic crust is formed at an oceanic ridge, while the lithosphere is subducted back into the asthenosphere at trenches. Oceanic trenches are prominent, long, narrow topographic depressions of the ocean floor. They are typically 50 to 100 kilometers (30 to 60 mi) wide and 3 to 4 km (1.9 to 2.5 mi) below the level of the surrounding oceanic ...
Mid-ocean ridge cross-section (cut-away view) 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 ...
During the most recent ice age (at its maximum about 20,000 years ago) the world's sea level was about 130 m lower than today, due to the large amount of sea water that had evaporated and been deposited as snow and ice, mostly in the Laurentide Ice Sheet. Most of this had melted by about 10,000 years ago.