IngGeo 214 Lecture Notes - 3 Plate tectonics - Plaat tektoniek

Plate Tectonics

A theory that Earth’s lithosphere consists of ~20 distinct pieces (plates) that slowly move relative to one another.

Pangaea

The supercontinent that existed during the late Paleozoic and early Mesozoic eras, which eventually fragmented into the continents we see today.

Continental Drift Hypothesis

The idea that Earth's continents move relative to each other, appearing to drift across the ocean bed.

Sea-floor Spreading

The process by which new ocean floor forms between diverging tectonic plates, causing continents to drift apart.

Subduction

The process where one tectonic plate sinks beneath another into the Earth's mantle.

Wadati-Benioff Zone

A zone of earthquakes that occur in a downgoing plate to a depth of 660 km.

Accretionary Prism

A wedge-shaped mass that includes sediment deposited on the surface of a downgoing plate that gets scraped up during the subduction process.

Volcanic Arc

A chain of volcanoes that forms behind an accretionary prism at a convergent tectonic plate boundary.

Divergent Plate Boundary

A plate boundary where two tectonic plates move away from each other.

Convergent Plate Boundary

A plate boundary where two tectonic plates move toward each other, resulting in one plate sinking beneath the other.

Transform Boundary

A plate boundary where one tectonic plate slips past another along a fault.

Hot Spots

Regions where a plume of hot mantle rock rises from just above the core-mantle boundary, causing volcanic activity at isolated points.

Triple Junction

The point where three tectonic plate boundaries meet.

Magnetic Inclination

The angle at which a magnetic needle tilts, which changes with latitude.

Magnetic Reversals

Periods when Earth’s magnetic field flips, causing the magnetic poles to switch places.

Paleomagnetism

The record of ancient magnetism preserved in rocks, used to study the historical movement of tectonic plates.

Earthquake Belts

Narrow, distinct bands where the positions of earthquake epicenters occur, defining the locations of plate boundaries.

Mid-Ocean Ridges

Underwater mountain ranges formed by tectonic plates diverging and allowing magma to rise and solidify.

Fracture Zones

Narrow bands of vertical fractures in the ocean floor that occur at right angles to mid-ocean ridges.

Coal Deposits

Accumulations of thick deposits of plant material in tropical climates that define certain climate belts on Pangaea.

Fossil Distribution

The geographic occurrence of fossils which provides evidence for continental drift by showing how land-dwelling species were once contiguous.