Plate Tectonics and Continental Drift

This set of flashcards covers key vocabulary related to plate tectonics, continental drift, and related geological phenomena.

Lithosphere

The rigid outer shell of the Earth, composed of the crust and upper mantle, divided into tectonic plates.

Asthenosphere

The ductile region of the upper mantle beneath the lithosphere that enables plate movement.

Continental Drift Hypothesis

Alfred Wegener's theory suggesting all continents were once merged into the supercontinent Pangaea, which later fragmented.

Pangaea

The supercontinent that existed when all continents were joined, surrounded by the ocean Panthalassa.

Laurasia and Gondwanaland

The two landmasses that emerged after Pangaea broke apart, consisting of modern-day North America, Europe, and Asia, and South America, Africa, India, Australia, and Antarctica, respectively.

Seafloor Spreading

The process of new oceanic crust forming at mid-ocean ridges and moving outward, discovered in the mid-20th century.

Divergent Boundary

A tectonic boundary where plates move apart, leading to the creation of new crust, exemplified by the Mid-Atlantic Ridge.

Convergent Boundary

A tectonic boundary where plates collide, forming subduction zones or mountain ranges.

Transform Boundary

A plate boundary where plates slide past each other horizontally, such as the San Andreas Fault.

Paleomagnetism

The study of Earth's ancient magnetic field recorded in rocks, supporting theories of plate movement.

Magnetic Reversals

The phenomenon of symmetrical magnetic stripes on either side of mid-ocean ridges indicating polarity changes.

Hot Spot Volcanism

Volcanic activity occurring as a plate moves over a stationary mantle plume, forming chains like the Hawaiian Islands.

Subduction Zones

Regions where one tectonic plate moves under another, leading to oceanic trench formation.

Ridge Push

A mechanism of plate motion where gravity pushes plates away from elevated mid-ocean ridges.

Slab Pull

A mechanism where subducting plates pull the rest of the tectonic plate along with them.

Mantle Convection

The heat-driven flow within the mantle that drives the movement of tectonic plates.

Seismicity

The occurrence of earthquakes in relation to tectonic plate boundaries, with deep earthquakes indicating subduction zones.

Philippine Sea Plate

A tectonic plate located in the western Pacific, associated with significant volcanic and seismic activity.

Volcanic Activity

The occurrence of eruptions and the formation of volcanoes, particularly prevalent in the Pacific Ring of Fire.

Trench

A deep, long, and narrow depression in the ocean floor formed at convergent boundaries where subduction occurs.

Continental Collision

An event occurring at convergent boundaries where two continental plates collide, leading to the formation of mountain ranges.