How Does The Strength Of Continental Crust Vary With Depth

How Does The Strength Of Continental Crust Vary With Depth?

How does the strength of continental crust vary with depth? … Rocks become stronger with depth and then get weaker deep in the crust.

How would a rock respond to stresses applied at depth?

the rock will snap back to nearly its original size and shape when the stress is removed. … increases with depth as the thickness of the overlying rock increases. Squeezes the materials in Earth’s crust which makes it stronger and thus harder to break.

Why does continental crust stand higher on the mantle than oceanic crust?

Areas of continental crust stand higher than areas of oceanic crust because continental crust is THICKER and LESS DENSE than oceanic crust. The deepest parts of the ocean are near the continents and out in the middle of the ocean the water is relatively shallow.

What are the characteristics of continental crust?

Continental crust is broadly granitic in composition and with a density of about 2.7 grams per cubic cm is somewhat lighter than oceanic crust which is basaltic (i.e. richer in iron and magnesium than granite) in composition and has a density of about 2.9 to 3 grams per cubic cm.

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Why is the continental crust thicker?

The continental crust is the layer of granitic sedimentary and metamorphic rocks which form the continents and the areas of shallow seabed close to their shores known as continental shelves. … The crust is thickened by the compressive forces related to subduction or continental collision.

Why do rocks become stronger with depth in shallow levels of the crust?

“Rocks in the upper crust become STRONGER/WEAKER with depth because increasing confining pressure acts to hold rocks together and makes slipping along any fractures more difficult.”

How do geologists determine the stability conditions of minerals buried at great depths?

True or false: a rock becomes permanently deformed when even a small amount of stress is applied to it. If a rock is only subjected to heating and burial pressures during metamorphism (no differential stresses are applied) what may occur? What types of deformation and metamorphism may occur in extensional settings?

How does continental crust differ from oceanic crust?

Oceanic crust differs from continental crust in several ways: it is thinner denser younger and of different chemical composition. Like continental crust however oceanic crust is destroyed in subduction zones.

Why are continents higher than oceanic crust quizlet?

The continental crust is much less dense than the oceanic crust which means it rises higher above the mantle than the oceanic crust.

How do the differences between continental and oceanic crust affect the way plates interact?

The convergent boundaries between ocean and continental plates create subduction zones. The oceanic plate is pushed under the continental plate and melted. … The rocks and geological layers are much older on continental plates than in the oceanic plates. The Continental plates are much less dense than the Oceanic plates.

How do the average thickness and composition of continental crust differ from those of oceanic crust?

Continental crust is less dense. How do the average thickness and composition of continental crust differ from those oceanic crust? Continental crust is thicker and granite in composition. What is the direction of crustal movement of the Indian-Australian plate?

Which of the following best describes the continental crust?

The continental crust is the layer of granitic sedimentary and metamorphic rocks which form the continents and the areas of shallow seabed close to their shores known as continental shelves. It is less dense than the material of the Earth’s mantle and thus “floats” on top of it.

Where is the maximum thickness of crust found and why?

Answer: Ocean basins have 6–7 km thick crust (not including 4–5 km of water) and continents have an average thickness of 39.7 km. The crust is typically 30 km thick at the ocean-continent margin and gradually increases toward the continental interior to 40–45 km.

Which crust is thicker and what makes it thicker than the other?

Oceanic crust is thinner and denser than continental crust. Continental crust is much thicker than oceanic crust. It is 35 kilometers (22 miles) thick on average. All three major rock types—igneous metamorphic and sedimentary—are found in the crust.

How thickness is continental crust under mountain ranges?

The seismic data also show that the thickness of the continental crust ranges from 30 to 50 kilometers (18−30 miles) and that of the oceanic crust from about 5 to 8 kilometers (3−5 miles). Continental crust is thickest under mountain ranges where it bulges downward into the mantle forming a mountain root.

What are the four factors that influence the strength of a rock and how it will deform?

 Factors that influence the strength of a rock and how it will deform include temperature confining pressure rock type and time. Stress is the force per unit area acting on a solid.

Which type of deformation do rocks typically exhibit at depth within the Earth where temperatures and pressures are elevated?

ductile deformation

This is known as ductile deformation and the rock is said to behave plastically. 5. Rocks under low confining pressures near the earth’s surface therefore generally deform through fracturing and faulting. Rocks deep within the crust under high confining pressures deform by folding.

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How does the movement of tectonic plates cause deformation in rock?

Plate tectonics can cause continental crustal blocks to collide. When this occurs the rocks between the two continental blocks become folded and faulted under compressional stresses and are pushed upward to form fold-thrust mountains.

What are the changes undergone by rocks that are buried at great depths?

Metamorphism occurs because rocks undergo changes in temperature and pressure and may be subjected to differential stress and hydrothermal fluids. … Temperature increases with depth in the Earth along the Geothermal Gradient. Thus higher temperature can occur by burial of rock.

Why does regional metamorphism usually occur within the continental crust?

Most regional metamorphism takes place within continental crust. … Because this metamorphism takes place at temperatures well below the temperature at which the rock originally formed (~1200°C) it is known as retrograde metamorphism.

How do geologists recognize faults using the laws and principles of geologic time from Chapter 9 choose all that apply?

How do geologists recognize faults using the laws and principles of geologic time from Chapter 9? … Dip-slip faults offset sedimentary strata in the vertical plane the principle of cross-cutting relations applies.

How is continental crust different from oceanic crust quizlet?

The oceanic crust is thinner and denser and is similar in composition to basalt (Si O Ca Mg and Fe). The continental crust is thicker and less dense and is similar to granite in composition (Si O Al K and Na). … The outer core is liquid iron and the inner core is solid iron.

Why do continental plates tend to move slower than oceanic plates?

Each plate moves a little differently for example Continental Plates tend to move slower because their roots are located deep in the mantle while Oceanic Plates move faster.

What are the reasons oceanic crust sits below continental?

Because ocean crust is more dense than continental crust it will sink beneath continents if tectonic forces push the oceanic crust into the continent.

What happens in continental continental convergence?

When two continental plates converge they smash together and create mountains. The amazing Himalaya Mountains are the result of this type of convergent plate boundary.

What are three differences between continental and oceanic crust?

Continental crust is low in density whereas oceanic crust has a higher density. Continental crust is thicker on the contrary the oceanic crust is thinner. Continental crust floats on magma freely but oceanic crust floats on magma scarcely. Continental crust cannot recycle whereas oceanic crust can recycle it.

What happens when a continental crust collides with an oceanic crust?

When an oceanic and a continental plate collide eventually the oceanic plate is subducted under the continental plate due to the high density of the oceanic plate. … As time goes on the hot magma rising upward from the subduction zone causes further compression of the mountain belt.

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How are the types of crust different from each other?

There are two different types of crust: thin oceanic crust that underlies the ocean basins and thicker continental crust that underlies the continents. … The thin oceanic crust is composed of primarily of basalt and the thicker continental crust is composed primarily of granite.

What causes the thickness of the crust to vary?

At convergent plate boundaries where tectonic plates crash into each other continental crust is thrust up in the process of orogeny or mountain-building. For this reason the thickest parts of continental crust are at the world’s tallest mountain ranges.

What is the thickness of continental crust?

Global observations show that the crustal thickness varies through the tectonic regions. While the continental crust is 30–70 km thick the oceanic crustal thickness is 6–12 km. The oceanic crust is also denser (2.8–3.0 g/cm3) than the continental crust (2.6–2.7 g/cm3).

Why does continental crust stand higher on the mantle than oceanic crust?

Areas of continental crust stand higher than areas of oceanic crust because continental crust is THICKER and LESS DENSE than oceanic crust. The deepest parts of the ocean are near the continents and out in the middle of the ocean the water is relatively shallow.

Why is continental crust older?

It is due to the process of subduction oceanic crust tends to get colder and denser with age as it spreads off the mid-ocean ridges. … As the continental crust is lighter than the oceanic crust the continental crust cannot subduct. We therefore still have some very old continental rocks at the surface of the Earth.

Does the thickness of the Earth’s crust vary?

The thickness varies depending on where you are on earth with oceanic crust being 5-10 km and continental mountain ranges being up to 30-45 km thick. Thin oceanic crust is denser than the thicker continental crust and therefore ‘floats’ lower in the mantle as compared to continental crust.

Where is the continental crust thinnest?

rift zones
The thinnest continental crust is found in rift zones where the crust is thinned by detachment faulting and eventually severed replaced by oceanic crust. The edges of continental fragments formed this way (both sides of the Atlantic Ocean for example) are termed passive margins.

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