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The Vine–Matthews–Morley hypothesis, also known as the Morley–Vine–Matthews hypothesis, was the first key scientific test of the seafloor spreading theory of continental drift and plate tectonics. Its key impact was that it allowed the rates of plate motions at mid-ocean ridges to be computed.
The key principle of plate tectonics is that the lithosphere exists as separate and distinct tectonic plates, which ride on the fluid-like solid the asthenosphere. Plate motions range from 10 to 40 millimetres per year (0.4 to 1.6 in/year) at the Mid-Atlantic Ridge (about as fast as fingernails grow), to about 160 millimetres per year (6.3 in ...
Rather than introducing another extraneous theory, these explanations essentially expand the scope of plate tectonics in ways that can accommodate volcanic activity previously thought to be outside its remit. The key modification to the basic plate-tectonic model here is a relaxation of the assumption that plates are rigid.
In passive rifting, driven by plate tectonics, the crust and lithosphere extend as a result of plate boundary forces such as slab pull. [10] Far field stresses thin the crust and lithospheric mantle, and hot asthenospheric mantle passively enters the thinned area. [10] The upwelling of asthenosphere is not involved in the actual rifting process.
[4] [5] The theory can be summarized by the phrase "the present is the key to the past." [ 6 ] Hutton also described the concept of deep time. The prevailing conceptualization of Earth history in 18th-century Europe, grounded in a literal interpretation of Christian scripture , was that of a young Earth shaped by catastrophic events.
The Wilson cycle theory is based upon the idea of an ongoing cycle of ocean closure, continental collision, and a formation of new ocean on the former suture zone.The Wilson Cycle can be described in six phases of tectonic plate motion: the separation of a continent (continental rift), formation of a young ocean at the seafloor, formation of ocean basins during continental drift, initiation of ...
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).
Indo-Australian plate – Major tectonic plate formed by the fusion of the Indian and Australian plates (sometimes considered to be two separate tectonic plates) – 58,900,000 km 2 (22,700,000 sq mi) Australian plate – Major tectonic plate separated from Indo-Australian plate about 3 million years ago – 47,000,000 km 2 (18,000,000 sq mi)