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Spreading rate is the rate at which an ocean basin widens due to seafloor spreading. (The rate at which new oceanic lithosphere is added to each tectonic plate on either side of a mid-ocean ridge is the spreading half-rate and is equal to half of the spreading rate). Spreading rates determine if the ridge is fast, intermediate, or slow.
The first discovered mid-ocean ridge was the Mid-Atlantic Ridge, which is a spreading center that bisects the North and South Atlantic basins; hence the origin of the name 'mid-ocean ridge'. Most oceanic spreading centers are not in the middle of their hosting ocean basis but regardless, are traditionally called mid-ocean ridges.
The ridge is a medium rate spreading center, moving outwards at a rate of approximately 6 centimetres (2.4 in) per year. [14] Tectonic activity along the ridge is monitored primarily with the U.S. Navy's Sound Surveillance System (SOSUS) array of hydrophones, allowing for real time detection of earthquakes and eruptive events. [10]
As the old spreading center ceases, the new rift forms the new spreading center. Interaction with a migrating hotspot is described as a migrating hotspot intrusion zone. Under this scenario, a hotspot (with high heating rate) nearing a spreading center causes asymmetrical lithospheric thinning over a broad region, which further leads to ...
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]
Seafloor spreading creates mid-ocean ridges along the center line of major ocean basins, where the seabed is slightly shallower than the surrounding abyssal plain. From the abyssal plain, the seabed slopes upward toward the continents and becomes, in order from deep to shallow, the continental rise, slope, and shelf.
Central Basin Spreading Center (CBSC), formerly Central Basin Fault, is a seafloor spreading center of the West Philippine Basin. [1] It is a long, NW-SE-trending structure that is considered to have been the spreading center of the West Philippine Basin (WPB) from the Eocene to the middle Oligocene.
The seafloor spreading center jumps three times, at 25.5 Ma, at 24.7 Ma and at 20.5 Ma. [7] These jumps are regarded as the boundaries of the three sea floor spreading episodes that moved the extension to the south out of its original position in the Xisha Trough. Figure 4 shows the trajectory of the seafloor spreading center. 37 Ma to 25.5 Ma.