AICE Marine Science Earth Processes Vocabulary

Vocabulary flashcards covering key tectonic processes, ocean floor features, weathering, erosion, sedimentation, and shoreline morphologies based on AICE Marine Science AS Chapter 2.

Crust

The outermost layer of Earth made of solid rock, measuring $5\,\text{km}$ thick beneath ocean basins and $70\,\text{km}$ thick beneath continents.

Oceanic Crust

The thinnest type of Earth crust, composed of basaltic rocks filled with iron and magnesium, which is denser than continental crust and subducts.

Continental Crust

The thicker type of Earth crust, composed of granite that is less dense than oceanic crust.

Mantle

The layer underneath the crust composed of hot, semi-solid rock capable of slow movement, containing the viscous asthenosphere where convection currents occur.

Core

The center of the Earth made of iron and nickel under great pressure, consisting of a liquid outer core and a solid inner core.

Theory of Continental Drift

A theory proposed by Alfred Wegener in $1912$ suggesting that over $300\,\text{million}$ years ago, all continents were connected in a single supercontinent called Pangea.

Theory of Plate Tectonics

A revised form of the theory of continental drift providing a mechanism showing that the lithosphere is broken into sections called tectonic plates that move on top of the mantle.

Paleomagnetic Stripes

Alternating stripes of normal and reversed magnetic polarity in ocean floor crust, measured using magnetometers, serving as evidence for plate tectonics.

Convection Currents

Circular movements of fluid magma in the mantle caused by density differences from temperature changes, which move lithospheric plates at a rate of $2-5\,\text{cm/year}$.

Convergent Boundaries

Destructive tectonic plate boundaries where two or more plates come together, forming subduction zones, deep ocean trenches, volcanoes, earthquakes, and tsunamis.

Divergent Boundaries

Constructive tectonic plate boundaries where two or more plates move away from each other, allowing molten magma to push through and form mid-ocean ridges, rifts, volcanoes, and hydrothermal vents.

Transform Boundaries

Tectonic boundaries where two plates slide laterally next to each other, creating friction, seismic activity, and faults without creating or destroying crust.

Subduction Zones

Destructive zones formed at convergent plate boundaries where a denser lithospheric plate slides beneath another plate and melts in the asthenosphere.

Ring of Fire

A chain of volcanoes formed at convergent plate boundaries in the Pacific Ocean.

Tsunami

A long-wavelength, high-energy seabed wave caused by a sudden release of stored seismic energy during an earthquake, which slows down and increases exponentially in height near shallow water.

Abyssal Plains

Flat, sandy regions of the ocean floor found at transform boundaries or between boundaries, formed by sea-floor spreading and covered over time with sediment and organic material.

Hydrothermal Vents

Openings in the ocean floor along mid-ocean ridge systems characterized by extreme pressure exceeding $200\,\text{atm}$ and superheated, mineral-rich water released at temperatures over $350^\circ\text{C}$.

Hydrothermal Vent Chimney

A structure up to $60\,\text{m}$ high formed when superheated, mineral-rich water meets near-freezing ocean water, causing dissolved metal sulfides to precipitate and solidify.

Weathering

The chemical and physical processes that break down rock at Earth's surface.

Erosion

The process by which water, ice, wind, or gravity moves weathered rock or soil from one location to another.

Deposition (Sedimentation)

The process in which suspended particles and sediment are laid down in new locations.

Chemical Weathering

The breakdown of rock where the chemical composition changes through exposure to water, rain, oxygen, or ocean salts.

Physical Weathering

Also known as mechanical weathering, the breakdown of rock into smaller pieces without changing its chemical composition, caused by temperature changes, freezing water, or waves.

Biological Weathering

The breakdown of rock that relies on living organisms through physical or chemical processes.

Littoral Zone

The intertidal region on a shoreline situated between the highest and lowest spring tide marks.

Rocky Shores

Shorelines made of erosion-resistant granite displaying a steep to wide gradient, with large boulders at the high water mark and smaller rocks near the low water mark due to high wave speeds.

Sandy Shores

Shorelines composed of loose sand, gravel, and shells formed by sandstone erosion and deposition, characterized by a gradual slope and constant movement by wind and waves.

Muddy Shores

Shorelines found in protected areas with minimal water movement and flat or shallow slopes, formed primarily through the sedimentation of fine silt and organic material.