UNIT 2 Set

Core

The innermost, dense sphere of the Earth, composed of iron and nickel.

Mantle

The layer between the core and the crust, composed of hot, semi-solid, molten rock capable of slow movement.

Crust

The outermost layer of the Earth, a solid rock shell.

Lithosphere

The rigid outer part of the Earth, consisting of the crust and upper solid mantle.

Asthenosphere

The upper layer of the Earth's mantle, below the lithosphere, with relatively low resistance to plastic flow.

Tectonic Plates

Large sections of the Earth's lithosphere that float on the asthenosphere.

Plate Tectonics

The theory that the Earth's lithosphere is divided into tectonic plates that move relative to each other.

Seafloor Spreading

The process by which new oceanic crust is formed through volcanic activity at mid-ocean ridges.

Paleomagnetic Striping

Alternating bands of normal and reversed magnetic polarity in rocks on either side of a mid-ocean ridge.

Convergent Boundary

A plate boundary where two tectonic plates move towards each other.

Subduction Zone

An area where one tectonic plate slides beneath another.

Divergent Boundary

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

Mid-Ocean Ridge

An underwater mountain range formed by plate tectonics, typically at a divergent boundary.

Hydrothermal Vent

An opening in the seabed where superheated water, rich in dissolved minerals, is released.

Transform Boundary

A plate boundary where two tectonic plates slide past each other horizontally.

Weathering

The gradual breakdown of rocks and minerals into smaller pieces.

Erosion

The process by which weathered material is transported from one place to another.

Sedimentation

The deposition of suspended particles (sediments) in a new location.

Littoral Zone

The area along a shoreline affected by tides and waves; the intertidal zone.

Tides

The periodic rise and fall of the surface of large bodies of water due to the gravitational pull of the Moon and Sun.

Spring Tide

A tide with the greatest difference between high and low water, occurring during a new or full moon.

Neap Tide

A tide with the least difference between high and low water, occurring during the first and third quarter moons.

Ocean Currents

Continuous, directed movement of seawater.

Thermohaline Circulation

Deep ocean currents driven by differences in temperature and salinity.

Upwelling

The upward movement of cold, nutrient-rich water from the deep ocean to the surface.

Downwelling

The downward movement of surface water into the deeper ocean.

Coriolis Effect

An apparent deflection of moving objects caused by the Earth's rotation.

El Niño

The warm phase of the El Niño Southern Oscillation (ENSO), characterized by warmer sea surface temperatures.

La Niña

The cool phase of the El Niño Southern Oscillation (ENSO), characterized by cooler sea surface temperatures.

ENSO (El Niño Southern Oscillation)

A climate pattern that occurs across the tropical Pacific Ocean, characterized by fluctuating ocean temperatures.