Earth Science: Crust and Mantle Overview

Questions and Answers

What distinguishes oceanic crust from continental crust?

Continental crust is found primarily at mid-ocean ridges.

Oceanic crust is denser and primarily composed of basaltic rocks. (correct)

Continental crust consists of silicates with lower MgO content than oceanic crust.

Oceanic crust is less dense and similar to granite.

Which part of the Earth is responsible for generating its magnetic field?

The outer crust.

The liquid outer core. (correct)

The semi-fluid asthenosphere.

The solid inner core.

What is the primary composition of the mantle?

Solid basalt and granite.

Magnesium and iron oxides.

Silicates, specifically minerals with silicon and oxygen. (correct)

Iron and nickel.

How does the asthenosphere differ from the lower mantle?

<p>The asthenosphere behaves like a viscous liquid while the lower mantle is solid.</p> Signup and view all the answers

What defines the lithosphere?

<p>It consists of the crust and the upper mantle.</p> Signup and view all the answers

Study Notes

Crust

The outermost and thinnest layer of the Earth.
Composed mainly of silicates with lower magnesium oxide (MgO) content than the mantle.
Two distinct types exist:
- Oceanic crust: Denser, made primarily of basaltic rocks enriched with magnesium and iron.
- Continental crust: Less dense, primarily composed of rocks similar to granite.
Along with the upper mantle, the crust forms the lithosphere, characterized by being colder and brittle.
The lithosphere is divided into tectonic plates, which are involved in geological activities.

Mantle

The largest layer by volume located between the crust and the core.
Mainly composed of silicates, containing silicon and oxygen minerals.
Divided into two zones:
- Lower mantle: Solid in nature but undergoes gradual deformation and flow due to extreme pressure conditions.
- Asthenosphere: Although solid, behaves like a viscous liquid, providing the necessary mobility for tectonic plates, enabling their movement.

Core

The innermost layer of the Earth, primarily made of iron and nickel.
Divided into two sections:
- Inner core: Solid state maintained despite extremely high temperatures, due to the intense pressure present.
- Outer core: Liquid layer responsible for generating Earth's magnetic field through convection currents, playing a critical role in geodynamo processes.

Description

This quiz covers key concepts about the Earth's crust and mantle, including their composition, types of crust, and the role they play in the lithosphere. Understand the differences between oceanic and continental crust, as well as the characteristics of the mantle.