Geography: Lithosphere and Earth Internal Structure

Vocabulary flashcards covering the Earth's internal structure, seismic waves, crustal composition, tectonic structures, and plate boundary dynamics based on the lecture notes.

P-waves (Primary waves)

The fastest longitudinal seismic waves that can pass through both solid and liquid media.

S-waves (Secondary waves)

Slower transverse seismic waves that cannot pass through liquid media.

Lithosphere

The solid outer layer of the Earth consisting of the crust and the upper crystalline portion of the mantle; derived from Latin meaning stone or rocky layer.

Earth's Core

The central sphere of the Earth located between depths of $2900\, \text{km}$ and $6371\, \text{km}$, composed of iron and nickel with temperatures reaching $4000^\circ \text{C}$.

Outer Core

The physical state of the outer layer of Earth's core, which exists in a molten liquid state.

Inner Core

The innermost layer of the Earth with a radius of $1289\, \text{km}$, existing in a solid physical state.

Mantle

The intermediate layer of the Earth located between the crust and core from $30\, \text{km}$ to $2900\, \text{km}$ depth, meaning cloak or mantle in Latin and Greek.

Asthenosphere

A layer in the upper mantle located at a depth of approximately $150\text{--}200\, \text{km}$ with low density, strength, and viscosity that drives endogenous processes.

Mohorovičić boundary

The boundary separating the Earth's crust from the upper mantle where the velocity of seismic waves rapidly increases.

Granitic layer

A rock layer composed of lower-density minerals such as feldspar and mica; granite derives from Greek meaning grain.

Basaltic layer

A hard rock layer composed of minerals such as magnetite, labradorite, and olivine; basalt derives from Greek meaning stone with iron.

Dominant elements of Earth's crust

Eight chemical elements (O, Si, Al, Fe, Ca, Na, K, Mg) making up $99\%$ of the crust's mass, led by Oxygen ($47\%$) and Silicon ($30\%$).

Platform

A stable, relatively motionless section of the Earth's crust.

Geosyncline

A mobile, active belt of the Earth's crust.

Shield

An exposed section of a platform basement where ancient crystalline rocks are exposed at the surface without sedimentary cover.

Plate (Platform cover)

A section of a platform basement covered by various sedimentary rock layers.

Continental drift hypothesis

The concept proposed by 20th-century German scientist Alfred Wegener suggesting that continents move across Earth's surface.

Divergence

The tectonic process where lithospheric plates move away from each other in opposite directions.

Convergence

The tectonic process where lithospheric plates collide or move toward one another.

Transform movement

The movement where lithospheric plates slide horizontally past one another parallel to their boundary.

Spreading

The process of horizontal extension of the Earth's crust where magma rises along mid-oceanic ridges to form new ocean floor.

Rift

A system or network of deep cracks and fractures in the Earth's crust, such as the Great East African Rift.

Collision

A type of convergence occurring specifically between two continental crusts, such as the interaction forming the Himalayas.

Subduction

The process where a thinner oceanic lithospheric plate sinks beneath an overriding continental or oceanic plate into the mantle.

Island arc

A chain of volcanic islands formed when one oceanic plate subducts beneath another oceanic plate.

Obduction

The tectonic process where oceanic crust is thrust or pushed onto the margin of a continental crust plate.

San Andreas Fault

A major transform fault $1300\, \text{km}$ in length that separates the North American plate from the Pacific plate.