Review of Short Phrases and Links|
This Review contains major "Oceanic Lithosphere"- related terms, short phrases and links grouped together in the form of Encyclopedia article.
- Oceanic lithosphere is less dense than asthenosphere for a few tens of millions of years, but after this becomes increasingly denser than asthenosphere.
- Oceanic lithosphere is typically about 50-100 km thick (but beneath the mid-ocean ridges is no thicker than the crust).
- Oceanic lithosphere is generally not denser than asthenosphere but continental lithosphere is lighter.
- Oceanic lithosphere is destroyed at subduction zones where lithosphere descends into the mantle beneath trenches.
- As oceanic lithosphere is formed at spreading ridges from hot mantle material it gradually cools and thickens with age (and thus distance from the ridge).
- In short, new oceanic lithosphere was created at the mid-ocen ridges and pushed older lithosphere.
- When this occurs, the heavier oceanic lithosphere sinks beneath the continental plate.
- The Sangihe trench was active at that time, subducting oceanic lithosphere of the Molucca Sea to the west.
- Thus old oceanic lithosphere will sink into the asthenosphere if it gets the chance.
- Thus, old oceanic lithosphere may have significant strength to depths in excess of 60 km or about half that of the thermal lithosphere.
- Nevertheless, it is often possible to look through the deformation and alteration and learn something about the structure of oceanic lithosphere.
- It suggests that the continents are less strong and less rigid than oceanic lithosphere.
- Diffuse plate boundaries, which are zones of deformation hundreds to thousands of kilometres wide, occur in both continental and oceanic lithosphere.
- D ivergence, and the creation of new oceanic lithosphere, can go on for tens or hundreds of millions of years.
- Oceanic lithosphere ranges from 50 km to 100 km in thickness, and continental lithosphere ranges from 40 km to 200 km.
- The thickness of the mantle part of the oceanic lithosphere can be approximated as a thermal boundary layer that thickens as the square root of time.
- Sea floor topography is controlled by the age of the oceanic lithosphere and the rate of spreading.
- This is the place where new oceanic lithosphere is made and how fast this is happening effects the topography of the ridge.
- Average oceanic lithosphere is typically 100 km thick[ 5]; its thickness is a function of its age: as time passes, it conductively cools and becomes thicker.
- Gabbro is also part of the oceanic lithosphere (ophiolite suite) forming as a thick layer below the top-most pillow lavas across all the oceanic floors.
- Earthquakes occur in the cold, brittle upper part of the oceanic lithosphere as it is subducted.
- A plate (also called lithospheric plate) is a massive, irregularly shaped slab of solid rock, generally composed of both continental and oceanic lithosphere.
- Only in a few places, mainly Iceland and the Afar region in northeastern Africa, rifting, which generates oceanic lithosphere, is occurring on land.
- Trenches form where oceanic lithosphere is subducted at a convergent plate margin, presently at a global rate of about a tenth of a square meter per second.
- The Molucca Sea is the only present day example of ocean basin closure as a result of subduction of oceanic lithosphere in two opposite directions.
- The net effect is that subduction efficiently removes old oceanic lithosphere.
- And, ridges in the deep oceans that rise above the abyssal plains and where new oceanic lithosphere is created are called oceanic ridges.
- New oceanic lithosphere, or at least the oceanic crust, is formed at constructive plate boundaries.
- Evolution of oceanic lithosphere: A driving force study of the Nazca plate.
- When oceanic lithosphere collides with continental lithosphere, the oceanic plate will descend into the subduction zone (Fig.
- Plates with continental lithosphere have lower relative velocities than plates with only oceanic lithosphere.
- When oceanic lithosphere collides with continental lithosphere, it subducts beneath the continental lithosphere.
- During plate collision and subduction, terranes may be scraped off the oceanic lithosphere and become part of the continent.
- The fractionation and solidification of these magmas form the ophiolite suite, the four layers of rock that form the oceanic lithosphere.
- Rifting is said to have enter an intermediate phase once new oceanic lithosphere begins to form through the creation of a new midocean ridge.
- New oceanic lithosphere forms through volcanism in the form of fissures at mid-ocean ridges which are cracks that encircle the globe.
- Oceanic lithosphere disappears into trenches at a global rate of about a tenth of a square meter per second.
- Oceanic lithosphere moves into trenches at a global rate of about a tenth of a square metre per second.
- Continental Volcanic Arc Mountains formed in part by igneous activity associated with the subduction of oceanic lithosphere beneath a continent.
- Subduction of the oceanic lithosphere beneath the continental lithosphere produces continental volcanic arcs that erupt mostly andesitic magma.
- One slab of oceanic lithosphere is pushed beneath another in a process called subduction.
- Thick, cold, dense oceanic lithosphere sinks at subduction zones, pulling the rest of the ocean plate.
- Slab-pull occurs where cold, dense oceanic lithosphere is subducted and pulls the trailing lithosphere along.
- In places where plate accretion has occurred, land masses may contain the dense, basaltic rocks that are usually indicative of oceanic lithosphere.
- Slab pull When the denser, heavier oceanic lithosphere sinks and pulls the rest of the tectonic plate with it.
- The plate represents oceanic lithosphere that lies beneath the Philippine Sea.
- Stein, C. and S. Stein, Comparison of plate and asthenospheric flow models for the evolution of oceanic lithosphere, Geophys.
- When ocean lithosphere runs into a plate with continental lithosphere, the oceanic lithosphere is subducted beneath the continental lithosphere.
- When two plates of oceanic lithosphere run into one another the subducting plate is pushed to depths where it causes melting to occur.
- Further west is the Juan de Fuca Ridge, where two plates of the oceanic lithosphere are spreading apart.
- The upper parts of the plates carry water in fractures, seafloor sediments, and the altered minerals of the oceanic lithosphere itself.
- Because oceanic lithosphere may get subducted, the age of the ocean basins is relatively young.
- Ophiolites occur in areas where obduction (the opposite of subduction) has pushed a section of oceanic lithosphere onto continental crust.
- Nevertheless, we have a fairly good understanding of the structure of the oceanic lithosphere from seismic studies and ophiolites.
- In addition, deep trenches that occur along zones where oceanic lithosphere descends back into the mantle are called oceanic trenches.
- Because oceanic lithosphere is cold and brittle, it fractures as it descends back into the mantle.
- At this point, the density of the oceanic lithosphere increases and it is carried into the mantle by the downwelling convective currents.
- Plates are able to move because of the relative density of oceanic lithosphere and the relative weakness of the asthenosphere.
- The density of oceanic lithosphere is similar to that of the asthenosphere, and it can thus fairly easily be pushed down into the uppermost mantle.
- As oceanic lithosphere moves away from the ridge, it cools and sinks deeper into the asthenosphere.
- Of the two plates, the one to be subducted is the plate with oceanic lithosphere.
- Oceanic subduction boundaries are those at which oceanic lithosphere is thrust (subducted) beneath either continental or oceanic lithosphere.
- Trenches form where oceanic lithosphere is subducted at a convergent plate margin, presently at a global rate of about a tenth of a square metre per second.
- Types The lithosphere is divided into two categories: the continental lithosphere and the oceanic lithosphere.
- The older of the two plates descends into the subduction zone when plates of oceanic lithosphere collide along a trench.
- Figure 8–11 shows magma forming in a subduction zone, where oceanic lithosphere is sinking beneath a continent.
- Water is driven out of the oceanic lithosphere in subduction zone s, and it causes melting in the overlying mantle.
- Interactions along convergent boundaries involve the collision of pairs of plates where oceanic lithosphere is often destroyed at subduction zones.
- The production of oceanic lithosphere at these ridges was accommodated through its destruction at subduction zones.
- Water is driven out of the oceanic lithosphere in subduction zones, and it causes melting in the overlying mantle.
- Oceanic lithosphere thickens as it ages and moves away from the mid-ocean ridge.
- Plates move apart, or diverge, at mid-ocean ridges where seafloor spreading forms new oceanic lithosphere.
- New oceanic lithosphere capped by basaltic crust is created at the mid-ocean ridges, and this newly formed plate moves away from the ridges.
- Back-arc spreading centres are similar to mid-ocean ridges, and produce new oceanic lithosphere in back-arc basins by sea-floor spreading.
- Crust is always less dense than asthenosphere or lithospheric mantle and continental lithosphere is always less dense than oceanic lithosphere.
- Oceanic Lithosphere The rigid, outermost layer of the Earth comprising the crust and upper mantle is called the lithosphere.
- Subduction zones exist at convergent plate boundaries where one plate of oceanic lithosphere converges with another plate and sinks below into the mantle.
- Mid-Ocean Ridges
- Subduction Zones
- Places > Earth > Geology > Lithosphere
- Events > Earthquakes > Plate Tectonics > Asthenosphere
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