What is an accretionary prism quizlet?
An accretionary prism is a wedge-shaped mass of sediment scraped off a subducting plate as it slides under the overriding plate. A spreading boundary must be in the middle of the ocean basin where it is located.
What is a accretionary prism in geology?
Accretionary prisms. The accretionary prism, also known as a subduction zone complex, consists of a series of steeply inclined, fault-bounded wedges of sediment and volcanic rock above a descending slab.
How does an accretionary wedge form?
Sediments, the top layer of material on a tectonic plate, that accumulate and deform where oceanic and continental plates collide. These sediments are scraped off the top of the downgoing oceanic crustal plate and are appended to the edge of the continental plate.
What island is part of an accretionary prism?
The Barbados Ridge Complex is the accretionary prism of the Lesser Antilles island arc subduction zone. Fig 13a shows the location of Barbados Island, the highest elevation of the accretionary prism, in the Caribbean Sea. As can be seen in Fig 13a, subduction has produced an island arc.
What is an accretionary wedge quizlet?
Accretionary wedge. a large wedge shaped mass of sediment that accumulates in subduction zones. Here sediment is scraped from the subducting oceanic plate and accreted to the over riding crustal block.
Is the lithosphere more mafic than asthenosphere?
Lithosphere is more mafic than asthenosphere. … Asthenosphere consists of the lower middle and upper mantle and is defined as mantle material that is cooler than 1280°C.
Which rock type makes up an accretionary wedge?
The primary rock type which forms at accretionary wedges is a jumbled, fractured sedimentary rock known as melange.
What type of fault is expected in an accretionary prism?
(a) The accretionary prism is obliquely truncated by a strike-slip fault.
What is a batholith and in what modern tectonic setting are Batholiths being generated?
What is a batholith? In what modern tectonic setting are batholiths being generated? Batholith: magma that intrudes the crust and never reaches the surface. Instead, it crystallizes at depth to form more massive igneous plutons. Modern batholiths are being created in Granite in the Sierra Nevada.
What composition of magma is initially generated in a subduction zone?
The initial magma formed as mantle rock melts beneath a subduction zone has low silica (basalt) composition. As the basalt magma rises up through the thick continental crust of North America, it melts some of that rock, too.
Is the lithosphere mafic?
The Earth has two types of lithosphere: oceanic and continental. The lithosphere is broken up into tectonic plates. Oceanic lithosphere consists mainly of mafic(rich in magnesium and iron) crust and ultramafic(over 90% mafic) mantle and is denser than continental lithosphere.
What is in the asthenosphere?
The asthenosphere is a part of the upper mantle just below the lithosphere that is involved in plate tectonic movement and isostatic adjustments. It is composed of peridotite, a rock containing mostly the minerals olivine and pyroxene.
What is an accretionary wedge in a subduction zone?
Accretionary Wedge (aka Accretionary Prism, Subduction Complex): A wedge- or prism-shaped mass of sediments and rock fragments which has accumulated where a downgoing oceanic plate meets an overriding plate (either oceanic or continental) at a subduction zone.
Do accretionary prisms occur at divergent boundaries?
Accretionary prisms occur at divergent boundaries.
What is an accretionary wedge briefly describe its formation quizlet?
Briefly describe its formation. An accretionary wedge is when there is an accumulation of sedimentary and metamorphic rock with occasional scraps of ocean crust.
What’s the definition of a batholith?
Definition: Despite sounding like something out of Harry Potter, a batholith is a type of igneous rock that forms when magma rises into the earth's crust, but does not erupt onto the surface.
What is formed at a subduction zone?
Oceanic trenches are formed at subduction zones. Oceanic plates meet continental plates in the water, so trenches are formed as the oceanic plate goes under the continental plate. These trenches can be very deep if the plate that is subducting (going down) is an older and colder plate.
Is the mantle mafic or felsic?
ultramafic rock Continental crust is felsic and oceanic crust is mafic. The mantle is hot, ultramafic rock.
What is lithosphere is composed of?
The lithosphere is the rocky outer part of the Earth. It is made up of the brittle crust and the top part of the upper mantle. The lithosphere is the coolest and most rigid part of the Earth.
What is asthenosphere answer?
The asthenosphere is a layer (zone) of Earth's mantle lying beneath the lithosphere. It is a layer of solid rock that has so much pressure and heat the rocks can flow like a liquid. The rocks are also less dense than the rocks in the lithosphere. It is believed to be much hotter and more fluid than the lithosphere.
Which layers make up the asthenosphere?
The asthenosphere is a part of the upper mantle just below the lithosphere that is involved in plate tectonic movement and isostatic adjustments. It is composed of peridotite, a rock containing mostly the minerals olivine and pyroxene.
What is the difference between Terrane and terrain?
What is the difference between terrane and terrain? "Terrane" describes a crustal fragment consisting of a distinct and recognizable series of rock formations that has been transported by plate tectonic processes, whereas "terrain" describes the shape of the surface topography.
What are batholiths and Laccoliths?
The batholith is a large irregular mass of intrusive igneous rocks that forces themselves in surrounding strata, and laccolith is a mass of igneous or volcanic rock within strata. Batholith and laccoliths are part of igneous rocks and volcanic landforms.
What is a batholith quizlet?
A batholith is a large emplacement of igneous intrusive rock that forms from cooled magma deep in the Earth's crust. Batholiths are almost always made mostly of felsic or intermediate rock-types, such as granite, quartz monzonite, or diorite. A stock is just smaller.
Where is a subduction zone?
Subduction zones are where the cold oceanic lithosphere sinks back into the mantle and is recycled. They are found at convergent plate boundaries, where the oceanic lithosphere of one plate converges with the less dense lithosphere of another plate.
What landforms are formed at a subduction zone?
Various formations such as mountain ranges, islands, and trenches are caused by subduction and the volcanoes and earthquakes it triggers.
What is felsic and mafic?
In geology, felsic is a modifier describing igneous rocks that are relatively rich in elements that form feldspar and quartz. It is contrasted with mafic rocks, which are relatively richer in magnesium and iron.
Why is the mantle mafic?
Mafic rocks contain minerals with less silica, but more iron and magnesium. Mafic rocks (and therefore ocean crust) are denser than the felsic rocks of continental crust. The crust floats on the mantle. Continental crust floats higher in the mantle than ocean crust because of the lower density of continental crust.
What are the layer of the lithosphere?
Earth's lithosphere. Earth's lithosphere, which constitutes the hard and rigid outer vertical layer of the Earth, includes the crust and the uppermost mantle. The lithosphere is underlain by the asthenosphere which is the weaker, hotter, and deeper part of the upper mantle.
What is lithosphere Byjus?
The lithosphere is the rigid, outermost shell on Earth. It is composed of the crust and the portion of the upper mantle that behaves elastically on time scales of thousands of years or greater. The outermost shell of a rocky planet, the crust, is defined on the basis of its chemistry and mineralogy.