Earth's Interior Quiz

Questions and Answers

Which layer of the Earth is characterized as a viscous molten rock?

Inner Core

Mantle (correct)

Outer Core

Crust

What is the average density of the Earth's crust?

3.0 g/cm³

4.0 g/cm³

2.7 g/cm³ (correct)

5.5 g/cm³

Which statement about oceanic and continental crust is true?

Continental crust is denser than oceanic crust.

Oceanic crust is composed of granite.

Oceanic crust consists mainly of felsic rocks.

Continental crust is generally thicker than oceanic crust. (correct)

Which of the following elements is most abundant in the Earth's crust by weight?

Oxygen (O) Signup and view all the answers

What is the depth range of the continental crust in relation to major mountain systems?

70-100 km Signup and view all the answers

The term 'felsic' in geology refers to which type of rocks?

Rich in lighter elements like silica and aluminum Signup and view all the answers

What does the Mohorovicic (Moho) discontinuity signify?

The transition from the crust to the mantle. Signup and view all the answers

What is the temperature increase rate per kilometer in the upper part of the Earth's crust?

30 °C Signup and view all the answers

Study Notes

Earth's Internal Structure

Earth consists of concentric layers: crust, mantle, outer core, and inner core, each with distinct physical and chemical properties.
Crust: silicate solid; Mantle: viscous molten rock; Outer Core: viscous liquid; Inner Core: dense solid.
Earth's mechanical layers: lithosphere, asthenosphere, mesospheric mantle, outer core, and inner core.
Chemical classification includes crust, upper mantle, lower mantle, outer core, and inner core.

Most Abundant Elements of the Earth's Crust

Oxygen (46.6%), Silicon (27.7%), Aluminum (8.1%), Iron (5.0%), Calcium (3.6%), Sodium (2.8%), Potassium (2.6%), Magnesium (1.5%).

Most Abundant Elements of the Earth

Iron (34.5%), Oxygen (29.5%), Silicon (15.2%), Magnesium (12.7%).

The Crust

Outermost layer, comprising 0.5-1.0% of Earth's volume and <1% of its mass.
Average density: ~2.7 g/cm³; density increases with depth.
Oceanic crust thickness: 5-30 km; Continental crust thickness: 50-70 km, up to 70-100 km in mountain ranges like the Himalayas.
Temperature ranges from 200 °C to 400 °C at the mantle boundary; temperature increases by ~30 °C per kilometer in the upper crust.
Composed of sedimentary materials on top, with crystalline, igneous, and metamorphic rocks underneath; lower crust includes basaltic and ultra-basic rocks.

Composition of Crust

Continental crust: lighter (felsic) sodium-potassium-aluminum silicate rocks, e.g., granite.
Oceanic crust: denser (mafic) iron-magnesium-silicate igneous rocks, e.g., basalt.
Felsic rocks are rich in silica, oxygen, aluminum, sodium, and potassium, contrasting with mafic rocks that have more magnesium and iron.
Classification terms: sial (lighter continental materials) and sima (heavier oceanic materials) are now considered somewhat outdated.

The Mohorovicic (Moho) Discontinuity

Marks the boundary between the Earth's crust and the underlying mantle, characterized by a transition in seismic activity and rock composition.

Description

Test your knowledge on the internal structure of the Earth, including its layers such as the crust, mantle, outer core, and inner core. Explore the unique physical and chemical properties of these layers and learn about the most abundant elements in the Earth's crust.