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Why is oceanic plate denser than continental plate?
Oceanic plates are primarily made up of basaltic rock while continental plates are primarily made of granitic rock. Basalt is denser than granite which allows oceanic plates to subduct beneath continental plates.
Why is the oldest ocean crust only 150 million years old?
Because the oldest parts reach the continental crust and then the ocean floor sinks beneath the continental crust, into the mantle.
A plate with oceanic crust sinking under another plate with oceanic crust?
When two oceanic plates or two plates both containing oceanic crust collide or converge, the convergent boundary will form a trench. The plate which has the higher density will plunge beneath the other plate forming a trench.
What are facts about the layers of the earth?
(All depths are from the surface of the Earth.) 1. The Crust--The outer skin of the planet is composed of igneous, metamorphic, and sedimentary rock. The crust is divided into continental or oceanic based on composition and formation. Continental Crust: Comprised predominately of rocks most resembling granite, the continental crust is relatively thick compared to the oceanic crust with a depth that ranges from 30 km to 50 km. The average specific gravity of continental crustal rock is 2.7. Oceanic Crust: At an average depth of 5 km to 10 km, the oceanic crust is thinner than the continental crust. Oceanic crustal rocks are composed mainly of the igneous rocks basalt, diabase, and gabbro, which are mafic in composition. The average specific gravity of oceanic crustal rock is 2.9. Lithosphere: See below. 2. The Mantle--The layer directly below the crust which is delineated from the crust by the Mohorovicic Discontinuity, where seismic waves increase in velocity. The division between the mantle and the crust is a chemical one, the rocks and constituent minerals being higher in magnesium and lower in silicon and aluminum than crustal rocks. The mantle comprises 84% of Earth's volume. The mantle can be further divided as follows: Upper Mantle:Lithosphere: The uppermost mantle consists of hard rock and is attached to the crust and comprises the lithosphere. The lithosphere is comprised of tectonic plates which 'float' independently of each other. The lithosphere contains more mantle than crust. Oceanic lithosphere ranges from 50 km to 100 km in thickness, and continental lithosphere ranges from 40 km to 200 km. Asthenosphere: Just below the lithosphere lies the asthenosphere, an area of highly viscous but solid rock. Its viscosity allow it to move slowly over time, which it does as it transfers heat to the lithosphere via convection currents. These convection currents are responsible for the movement of Earth's tectonic plates. The depth of the asthenosphere averages somewhere between 100 km and 200km with depths up to 410 km. Transition Zone: The depth of the transition zone is between 410 km and 660 km. The rock here is mostly peridotite, a coarse grained igneous rock, kept from melting by extremely high lithostatic temperatures. Temperatures in the transition zone range from 1400 degrees C to 1600 degrees C. The Lower Mantle: The depth of the lower mantle ranges from 670 km to 2798 km. Little is known about the lower mantle other than that seismic waves indicate it is fairly homogenous in lithology. D'': The D'' area of the mantle extends from 2798 km to 2900 km, which is the boundary between the mantle and the liquid outer core. At this level, the pressures are enormous, roughly equal to 1.4 million units of atmospheric pressure, and temperatures are over 4,000 degrees C. 3. The Outer Core: The outer core lies at a depth from 2900 km to 5150 km. It's composed of liquid iron and nickel along with small amounts of lighter elements, with temperatures ranging from 4,000 degrees C to 6,100 degrees C near the boundary with the inner core. 4. The Inner Core: From the boundary with the outer core to the center of the Earth, a distance of about 1220 km is the solid sphere of the inner core, a ball of incredibly hot iron-nickel alloy. Temperatures here reach between 5,000 and 7,000 degrees C, and pressures are calculated to be around 3,000,000 units of atmospheric pressure. Despite the high temperature, at these pressures the metals cannot remain molten. == == == == === === == ==
Describe the various layers of the earth?
1. The Crust--The outer skin of the planet is composed of igneous, metamorphic, and sedimentary rock.2. The Mantle--The layer directly below the crust which is delineated from the crust by the Mohorovicic Discontinuity, where seismic waves increase in velocity. The division between the mantle and the crust is a chemical one, the rocks and constituent minerals being higher in magnesium and lower in silicon and aluminum than crustal rocks. The mantle comprises 84% of Earth's volume.3. The Outer Core--The outer core lies at a depth from 2900 km to 5150 km. It's composed of liquid iron and nickel along with small amounts of lighter elements, with temperatures ranging from 4,000 degrees C to 6,100 degrees C near the boundary with the inner core.4. The Inner Core--From the boundary with the outer core to the center of the Earth, a distance of about 1220 km is the solid sphere of the inner core, a ball of incredibly hot iron-nickel alloy. Temperatures here reach between 5,000 and 7,000 degrees C, and pressures are calculated to be around 3,000,000 units of atmospheric pressure. Despite the high temperature, at these pressures the metals cannot remain molten.
Is continental crust darker in color than oceanic or lighter?
Continental crust is generally lighter in color than oceanic crust. This is because continental crust is composed of lighter-colored rocks such as granite, which contain lighter minerals like quartz and feldspar. In contrast, oceanic crust is made up of darker-colored rocks like basalt, which contain heavier minerals like pyroxene and olivine.
Why does the oceanic crust sit lower in the mantle than the continental crust?
Oceanic crust is denser than continental crust due to its composition and age, causing it to sink lower into the mantle. The oceanic crust is also thinner and has been subjected to more intense heat and pressure, which contributes to its lower position in the mantle compared to the thicker, lighter continental crust.
Is the continental crust thinner than the oceanic crust?
It is not. The oceanic crust is thinner than the continental crust!
Why does the oceanic sink beneath continental crust at convergent boundaries?
The continental crust is less dense than the oceanic crust. That's the reason we find that the oceanic crust sinks (subducts) beneath the continental crust.Continental crust is less dense than oceanic crust and so cannot sink below it.
What characteristics of continental crust allow it to float higher on the mantle than oceanic cruast?
Continental crust is less dense than oceanic crust because it is thicker and composed of lighter materials, such as granite. This lower density allows continental crust to "float" higher on the more dense mantle beneath it, creating continents.
What crust is heavier?
Continental crust is generally lighter than oceanic crust because it is thicker and less dense. Oceanic crust, being thinner and denser, tends to be heavier.
True or false continental crust is made of rocks such as granite?
True. Continental crust is primarily composed of lighter rocks such as granite, which are less dense than the basaltic rocks found in oceanic crust. This is why continental crust is thicker and less dense than oceanic crust.
What is older the oceanic crust or the continental crust?
Continental crust is far older than oceanic crust.
Which is denser Oceanic Crust or Continental Crust?
Oceanic crust is denser than continental crust because it is composed of denser rocks like basalt and gabbro, while continental crust is made up of lighter rocks like granite and sedimentary rocks. This density difference is due to the composition and thickness of each type of crust.
Oceanic crust is than continental crust.?
younger
What crust is older in years the continental or the oceanic?
Continental crust is far older than oceanic crust.
Why does ocenaic crust sink beneath the continental crust at a subduction boundary?
Oceanic crust is denser than continental crust due to its composition of basaltic rock and higher iron content. This density difference causes oceanic crust to sink beneath the lighter continental crust at subduction zones, creating a convergent boundary. The descending oceanic plate creates deep oceanic trenches and can trigger volcanic activity when it melts and rises to the surface.
