Earth's Differentiation and Layers

Which layer of the Earth is primarily composed of basalt rock?

What is the composition of the Earth's core primarily made of?

At what depth does the mantle begin to flow slowly?

Which term describes the outermost layer of the Earth?

What is the primary reason oceanic crust is denser than continental crust?

Which layer of the Earth is responsible for the flow of heat through convection?

What characteristic is associated with the lithosphere layer of the Earth?

Which layer of the Earth is described as being rigid and can bend slightly but not flow?

What characterizes the asthenosphere?

Which of the following is responsible for the generation of Earth's magnetic field?

What does the Mohorovičić Discontinuity separate?

How does the inner core differ from the outer core in terms of its state under pressure?

What is the main reason that plates in the lithosphere can move over the asthenosphere?

Earth's Differentiation

Earth is separated into concentric layers based on composition and density
Dense materials like iron and nickel sank to form the core
Lighter silicates rose to form the mantle and crust

Compositional Layers

Based on material composition
Crust: Outermost; oxygen is most abundant
- Continental Crust: 20-90km thick; less dense (2.7g/cm³); mainly granite & andesite; more pores
- Oceanic Crust: 5-10km thick; denser (3g/cm³); mainly basalt; fewer pores
Mantle: Beneath the crust; ~2,900km thick; 67% Earth's mass; solid rock; density ranging from 3.5-5.5 g/cm³; made of ultramafic rock called peridotite
Core: Innermost; iron-nickel alloy; 31% of Earth's composition; source of internal heat
- Outer Core: ~2,255km thick; liquid due to high temperature; responsible for Earth's magnetic field
- Inner Core: ~1,220km thick; solid due to intense pressure; slightly faster rotation due to magnetic field

Mechanical Layers

Based on temperature and seismic wave penetration
Lithosphere: Rigid, solid (upper mantle + crust); broken into plates that move over the asthenosphere
Asthenosphere: Part of upper mantle; 'plastic' and flows slowly; heated to 1280°C or 2330°F
Lower Mantle/Mesosphere: Region of increased pressure; lowest part of mantle, near outer core

Plate Tectonic Theory

Lithosphere is divided into individual pieces (plates)
Plates move over the asthenosphere due to convection currents

Boundaries and Seismic Discontinuities

Seismic discontinuity: Abrupt change in seismic wave velocity at boundaries
Mohorovičić Discontinuity: Boundary between crust and mantle; named after seismologist Andrija Mohorovičić
Andrija discovered a change in seismic wave behavior at depths greater than 200km

Explore the Earth's structure through its concentric layers, including the crust, mantle, and core. Learn about how materials like iron, nickel, and silicates are distributed and how each layer contributes to the planet's composition and behavior. This quiz will deepen your understanding of Earth's geological foundations.