Questions and Answers
What is the primary composition of the outer core?
What happens to S-waves at the Gutenberg Discontinuity?
Which layer of the Earth is characterized by a solid composition and high density?
Who discovered the Mohorovicic Discontinuity and when?
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What is the average depth of the Mohorovicic Discontinuity under the continental crust?
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What defines the boundary separating the outer core and inner core?
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Which layer of the Earth is primarily composed of silicate materials?
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What layer of the Earth is solid yet located in a liquid environment?
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What characterizes the oceanic crust compared to the continental crust?
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Which statement accurately describes the lithosphere?
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What distinguishes the upper mantle from the lower mantle?
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Which of the following accurately describes the core of the Earth?
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How thick is the mantle compared to the Earth’s total mass?
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What mineral compositions does 'sima' represent in the oceanic crust?
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In which part of the mantle are rocks considered to be partially molten?
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Which statement about the oceanic and continental crust is incorrect?
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Study Notes
Earth's Structure
- Earth consists of three major layers: Crust, Mantle, and Core.
Crust
- Outermost layer made of solid rocks and minerals.
- Two classifications:
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Oceanic Crust
- Extends 5 to 10 kilometers beneath the ocean floor.
- Composed of basalts; referred to as “sima” (silicate and magnesium).
- Dense and thin, formed at mid-ocean ridges.
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Continental Crust
- Composed mainly of granites, called “sial” (silicate and aluminum).
- Thickness can be over 70 kilometers; lighter than oceanic crust.
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Oceanic Crust
Mantle
- Lies beneath the crust, comprised of solid rock.
- Extends to a depth of about 2900 kilometers, contributing to 67% of Earth's total mass.
- Temperature and pressure increase with depth; heat transfer from the core raises temperatures.
- Divided into two layers:
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Upper Mantle
- Extends from the crust to about 410 kilometers.
- Mostly solid but malleable areas contribute to tectonic activity; includes the lithosphere (outer solid part).
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Lower Mantle
- Extends from about 660 to 2700 kilometers deep.
- Hotter and denser than the upper mantle; includes the asthenosphere (semi-molten layer).
- Mesosphere is the lowest part, adjacent to the outer core.
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Upper Mantle
Core
- Extremely hot and dense, located about 2900 kilometers below the surface.
- Composed of two parts:
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Outer Core
- Liquid iron-nickel alloy; temperature ranges from 4000 to 5000 degrees Celsius.
- Responsible for generating Earth’s magnetic field.
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Inner Core
- Composed mainly of dense iron and nickel; not affected by high temperature due to its pressure.
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Outer Core
Layer Division
- Chemical division based on composition: Crust, Mantle, Core.
- Mechanical division based on temperature and phase: Lithosphere, Asthenosphere, Outer Core, Inner Core.
Discontinuities
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Mohorovicic Discontinuity (Moho)
- Boundary between crust and mantle; average depth of 8 km under oceans and 32 km under continents.
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Gutenberg Discontinuity
- Boundary where P-waves slow down, indicating the presence of molten materials in the outer core.
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Lehmann Discontinuity
- Boundary between inner and outer core; supports the understanding of a solid inner core and liquid outer core based on seismic wave analysis.
Thickness Measurements
- Crust: Average thickness of 32 km.
- Mantle: Approximately 2853 kilometers thick.
- Core: Outer Core around 2270 kilometers; Inner Core about 1216 kilometers thick.
Tectonic Plates
- Massive slabs of solid rock that form Earth's outer shell, responsible for geological activities such as earthquakes and volcanic eruptions.
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Description
Explore the Earth's interior through this quiz focused on its three major layers: the crust, mantle, and core. Delve into the characteristics and classifications of the crust, including oceanic and continental types. Test your knowledge of geological terms and concepts!
