Section 3 Flashcards
What generates Earth’s magnetic field?
Convection currents in the liquid outer core create a geodynamo effect
This magnetic field protects Earth from solar wind and cosmic radiation.
What is paleomagnetism?
The alignment of magnetic minerals in rocks with Earth’s magnetic field during formation
This preserves the direction and strength of the magnetic field.
What are magnetic reversals?
Periodic reversals in polarity recorded in basalt at mid-ocean ridges
These are evidence for seafloor spreading and plate tectonics.
What do magnetic stripes on the seafloor indicate?
Symmetrical patterns of magnetic anomalies that confirm seafloor spreading and tectonic plate movement
These stripes are critical for understanding plate tectonics.
What is the composition of the continental crust?
Thick, less dense, granitic composition
What is the composition of the oceanic crust?
Thin, denser, basaltic composition
What are the two layers that divide the mantle?
Lithosphere and Asthenosphere
Lithosphere is rigid, while Asthenosphere is plastic and flowing.
What is the outer core made of?
Liquid iron and nickel
What is the inner core composed of?
Solid iron and nickel due to immense pressure
What drives mantle convection?
Heat from the core and radioactive decay
This creates convection currents that influence tectonic plate movement.
What are the three types of seismic waves?
- Primary (P) Waves
- Secondary (S) Waves
- Surface Waves
What is the focus in relation to an earthquake?
The point within Earth where an earthquake originates
What is the epicenter?
The point on the surface directly above the focus of an earthquake
What is isostasy?
The equilibrium between Earth’s crust and mantle where crust ‘floats’ on the denser mantle
What is isostatic rebound?
The rise of the crust after being depressed by heavy loads, such as glaciers
Ongoing rebound occurs in regions like Scandinavia and Canada.
What are landforms primarily created by?
Tectonic activity and erosion
Examples include mountains, valleys, plateaus, and plains.
What are the processes of erosion?
- Water
- Wind
- Glaciers
What is the difference between weathering and erosion?
Weathering is the breakdown of rocks into smaller particles, while erosion is the transport of weathered material by agents like water, wind, and ice
