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Oceanisation
Oceanisation, or oceanization, is the process of formation of an ocean after continental rifting. The oceanisation is marked by the accretion of oceanic basalts between the drifting continental blocks and the incursion of marine waters and species in the rift basin. According to John Frederick Dewey in the 1960s the idea of continental drift was different to that of oceanisation which was "the mysterious metasomatism or transformation of continental crust into oceanic crust Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramaf ...". References Geology {{Geology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocean
The ocean is the body of salt water that covers approximately 70.8% of Earth. The ocean is conventionally divided into large bodies of water, which are also referred to as ''oceans'' (the Pacific, Atlantic, Indian Ocean, Indian, Southern Ocean, Antarctic/Southern, and Arctic Ocean),"Ocean." ''Merriam-Webster.com Dictionary'', Merriam-Webster, https://www.merriam-webster.com/dictionary/ocean . Accessed March 14, 2021. and are themselves mostly divided into seas, gulfs and Lists of bodies of water#Seawater bodies, subsequent bodies of water. The ocean contains 97% of Water distribution on Earth, Earth's water and is the primary component of Earth's hydrosphere, acting as a huge Ocean heat content, reservoir of heat for Earth's energy budget, as well as for its carbon cycle and water cycl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rifting
In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear Fault (geology), downfaulted depression, called a graben, or more commonly a half-graben with normal faulting and rift-flank uplifts mainly on one side. Where rifts remain above sea level they form a rift valley, which may be filled by water forming a rift lake. The axis of the rift area may contain volcanic rocks, and active volcanism is a part of many, but not all, active rift systems. Major rifts occur along the central axis of most mid-ocean ridges, where new oceanic crust and lithosphere is created along a divergent boundary between two tectonic plates. ''Failed rifts'' are the result of continental rifting that failed to continue to the point of break-up. Typically the transition from rifting to spreading develops at a triple junction where three converging rifts meet over a Hotspot (geology), hotspot. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basalts
Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt is chemically equivalent to slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. Basalt is also an important rock type on other planetary bodies in the Solar System. For example, the bulk of the plains of Venus, which cover ~80% of the surface, are basaltic; the lunar maria are plains of flood-basaltic lava flows; and basalt is a common rock on the surface of Mars. Molten basalt lava has a low viscosity due to its relatively low silica content (between 45% and 52%), resulting in rapidly moving lava flows that can spread over great areas before cooling and solidifying. Flood basalts are thick sequence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rift
In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben with normal faulting and rift-flank uplifts mainly on one side. Where rifts remain above sea level they form a rift valley, which may be filled by water forming a rift lake. The axis of the rift area may contain volcanic rocks, and active volcanism is a part of many, but not all, active rift systems. Major rifts occur along the central axis of most mid-ocean ridges, where new oceanic crust and lithosphere is created along a divergent boundary between two tectonic plates. ''Failed rifts'' are the result of continental rifting that failed to continue to the point of break-up. Typically the transition from rifting to spreading develops at a triple junction where three converging rifts meet over a hotspot. Two of these evolve to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Frederick Dewey
John Frederick Dewey (born 22 May 1937) is a British structural geologist and a strong proponent of the theory of plate tectonics, building upon the early work undertaken in the 1960s and 1970s. He is widely regarded as an authority on the development and evolution of mountain ranges. Biography Dewey was educated at Bancroft's School and Queen Mary and Imperial College at the University of London where he was awarded a BSc and PhD in geology. Following a period as lecturer at the University of Manchester (1960–64), the University of Cambridge (1964–1970) and Memorial University of Newfoundland (1971), Dewey was appointed Professor of Geology at the State University of New York at Albany. During this period he produced a series of classic papers centred on the history of the Appalachians in Newfoundland as well as the Scottish and Irish Caledonides. In later years, his research has concentrated upon producing a model to describe the development and orogenic history ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continental Drift
Continental drift is a highly supported scientific theory, originating in the early 20th century, that Earth's continents move or drift relative to each other over geologic time. The theory of continental drift has since been validated and incorporated into the science of plate tectonics, which studies the movement of the continents as they ride on plates of the Earth's lithosphere. The speculation that continents might have "drifted" was first put forward by Abraham Ortelius in 1596. A pioneer of the modern view of mobilism was the Austrian geologist Otto Ampferer. The concept was independently and more fully developed by Alfred Wegener in his 1915 publication, "The Origin of Continents and Oceans". However, at that time his hypothesis was rejected by many for lack of any motive mechanism. In 1931, the English geologist Arthur Holmes proposed mantle convection for that mechanism. History Early history Abraham Ortelius , Theodor Christoph Lilienthal (1756), Alexan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metasomatism
Metasomatism (from the Greek μετά ''metá'' "change" and σῶμα ''sôma'' "body") is the chemical alteration of a rock by hydrothermal and other fluids. It is traditionally defined as metamorphism which involves a change in the chemical composition, excluding volatile components. It is the replacement of one rock by another of different mineralogical and chemical composition. The minerals which compose the rocks are dissolved and new mineral formations are deposited in their place. Dissolution and deposition occur simultaneously and the rock remains solid. Synonyms of the word ''metasomatism'' are metasomatosis and metasomatic process. The word ''metasomatose'' can be used as a name for specific varieties of metasomatism (for example '' Mg-metasomatose'' and '' Na-metasomatose''). Metasomatism can occur via the action of hydrothermal fluids from an igneous or metamorphic source. In the igneous environment, metasomatism produces skarns, greisen, and may affect hornfel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continental Crust
Continental crust is the layer of igneous, metamorphic, and sedimentary rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as '' continental shelves''. This layer is sometimes called '' sial'' because its bulk composition is richer in aluminium silicates (Al-Si) and has a lower density compared to the oceanic crust, called '' sima'' which is richer in magnesium silicate (Mg-Si) minerals. Changes in seismic wave velocities have shown that at a certain depth (the Conrad discontinuity), there is a reasonably sharp contrast between the more felsic upper continental crust and the lower continental crust, which is more mafic in character. Most continental crust is dry land above sea level. However, 94% of the Zealandia continental crust region is submerged beneath the Pacific Ocean, with New Zealand constituting 93% of the above-water portion. Thickness and density The continental crust consists of various layers, with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceanic Crust
Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic cumulates. The crust lies above the rigid uppermost layer of the mantle. The crust and the rigid upper mantle layer together constitute oceanic lithosphere. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium. It is thinner than continental crust, or sial, generally less than 10 kilometers thick; however, it is denser, having a mean density of about 3.0 grams per cubic centimeter as opposed to continental crust which has a density of about 2.7 grams per cubic centimeter. The crust uppermost is the result of the cooling of magma derived from mantle material below the plate. The magma is injected into the spreading center, which consists mainly of a partly solidified crystal mush derive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
