Earth Science - Plate Tectonics and Seafloor Spreading

Flashcards covering the internal structure of the Earth, plate tectonics, geological processes like subduction and rifting, and evidence for the continental drift theory.

Oceanic crust

The denser and heavier layer of the Earth's crust compared to continental crust.

Continental crust

The less dense and lighter layer of the Earth's crust compared to oceanic crust.

Earthquake distribution and active volcanoes

Geologic features that share the same patterns and are mostly found along the plate boundaries.

Pacific Ring of Fire

The location where the majority of the world's active volcanoes are found because it hosts the Pacific Plate, the largest and most massive tectonic plate.

Continental volcanic arc

A geologic feature formed during the convergence between an oceanic and a continental plate.

Volcanic island arc

A geologic feature created by the convergence between two oceanic plates where the older plate subducts.

Folding

The process that occurs during the convergence of two continental plates, resulting in the formation of high mountains and mountain ranges.

Subduction

The geologic process when a denser and heavier oceanic plate dives and plunges into the asthenosphere.

Asthenosphere

The layer where a subducting slab descends, partially melts, and creates magma chambers that rise to the surface.

Convection current

The driving force in the mantle that causes tectonic plates to move, converge, diverge, and slide past one another.

Rift valley

A geologic feature formed by tension and rifting when a continental plate slowly breaks apart.

Seafloor spreading

A process occurring at the Mid-Ocean ridge during the divergence of oceanic plates, characterized by the stretching of the seafloor and solidification of fissures.

Transform plate boundary

A boundary where plates simply slide or grind past one another without collision, subduction, or the formation of volcanoes.

Fossil evidence

Evidence of a supercontinent where fossils of the same prehistoric reptile species were found on different continents separated by seawater they could not cross.

Coal deposit evidence

Discovered prehistoric tropical plant remains in Antarctica, suggesting the continent was once positioned near the equator.

Rock mountain evidence

The discovery that rock mountains on the eastern coast of South America and the western coast of Africa share similar composition, mineral content, and ages.

Wegener's Mechanism

The explanation that the drifting of continents was caused by centrifugal force due to the rotation of the Earth.

Hot particles (convection)

Particles that possess high kinetic energy due to high temperature, making them less dense and lighter so they move upward.

Cold particles (convection)

Particles that possess low kinetic energy due to low temperature, making them denser and heavier so they move downward.

Magnetic Reversal

Also called the Magnetic Flip; an event where the North Pole and South Pole transform positions due to changing flow in the Earth's liquid outer core.