Plate Tectonics: Core Concepts

Alfred Wegener

Who proposed the Continental Drift hypothesis?

The theory that Earth's continents have moved over geological time relative to each other, appearing to 'drift' across the ocean bed.

What is the Continental Drift hypothesis?

The 'jigsaw fit' of continents, particularly South America and Africa.

Name one piece of evidence supporting Continental Drift related to landmass shapes.

Identical fossil species found on continents now separated by vast oceans suggest these landmasses were once connected.

How do fossils support the Continental Drift hypothesis?

Similar rock formations and mountain ranges found on different continents that align when the continents are reassembled.

What evidence from rock types supports Continental Drift?

Evidence of ancient climates (e.g., glacial deposits) found in tropical regions, suggesting continents have moved from different climatic zones.

How do paleoclimates provide evidence for Continental Drift?

The process by which new oceanic crust is formed through volcanic activity at mid-ocean ridges and then gradually moves away from the ridge.

What is Seafloor Spreading?

Major and minor tectonic plates.

What are the two main categories of tectonic plates?

Oceanic ridges or continental rifting.

Name a type of divergent plate boundary.

Mid-oceanic ridges.

What geological feature is formed at an oceanic divergent boundary?

The continental crust pulls apart, forming rift valleys that can eventually lead to new ocean basins.

What happens at a continental rifting divergent boundary?

Oceanic-continental, oceanic-oceanic, and continental-continental.

Name the three types of convergent plate boundaries.

The denser oceanic plate subducts beneath the continental plate, forming volcanic arcs and trenches.

What occurs at an oceanic-continental convergent boundary?

A plate boundary where two plates slide horizontally past each other, resulting in frequent earthquakes.

What is a transform boundary?

Plate Tectonics.

What is the overarching theory that explains the movement of Earth's lithosphere?