Plate Tectonics and Earth Dynamics

Vocabulary practice flashcards covering plate tectonics, plate boundaries, geological structures, and Earth's interior layering based on lecture notes.

Continental Rift

A region within a continental plate that fractures under the effect of divergence movement, initiating the creation of oceans from continents.

Subduction Zone

A zone formed at an oceanic trench where the convergence of a continental and an oceanic lithospheric plate forces the oceanic plate to plunge downward.

Continental Collision

The convergence of two continental plates that causes structural deformations forming mountain ranges and leads to the closure of oceans.

Oceanic Ridge

An active boundary structure located in the middle of oceans where divergence between two lithospheric plates takes place, generating new oceanic floor.

Oceanic Trench

An active plate boundary located along the edges of continents or islands where oceanic lithosphere plunges into a subduction zone.

Mountain Range (Chaîne de montagne)

An aerial positive continental relief found on continents, created by convergence movements and continental plate collision.

Theory of Plate Tectonics

A scientific theory developed in the 1960s (recorded as "années D") that describes, predicts, and explains plate motions over geological time, confirmed notably by GPS.

GPS

A measurement technology that provided confirmation for plate tectonics by evidencing three specific types of plate movements: convergence, divergence, and coulissage (sliding).

Three Types of Plate Movements

The three modes of relative motion between lithospheric plates identified in plate tectonics: convergence, divergence, and coulissage.

Lithosphere

The rigid external shell of the Earth, divided into fifteen plates with an average thickness of $100\,\text{km}$, resting upon the underlying asthenosphere.

Asthenosphere

The ductile and less rigid layer located immediately beneath the lithosphere.

Seismic Wave Velocity Variations

Variations in the propagation speed of seismic waves at depth that enable scientists to distinguish the rigid lithosphere from the less rigid asthenosphere.

Tectonic Plate

A stable zone on the surface of the Earth bounded by belts of strong seismic and volcanic activity, dividing the Earth's surface into fifteen distinct plates.

Active Plate Boundaries

The dynamic borders separating tectonic plates, marked by structures such as mid-ocean ridges, oceanic trenches, and continental mountain chains.