Untitled Flashcards Set

Continental Drift

A geological theory proposed by Alfred Wegener in the early 20th century, suggesting that the continents were once joined together in a single massive landform known as Pangea, which gradually drifted apart over millions of years due to tectonic processes.

Seafloor Spreading

A geological process occurring at mid-ocean ridges where tectonic plates move apart, allowing magma from the mantle to rise and solidify, creating new oceanic crust while older crust is pushed away and eventually destroyed at subduction zones.

P-Waves

Primary seismic waves, the fastest type of seismic wave, which can travel through both solid and liquid materials, making them essential for understanding the Earth's internal structure.

S-Waves

Secondary seismic waves that travel more slowly than P-waves and can only propagate through solid materials, indicating the presence of a solid inner structure in the Earth.

Isostasy

The state of gravitational equilibrium between the Earth's lithosphere and asthenosphere, which describes how the Earth's crust 'floats' on the more viscous mantle, resulting in varying elevations and topographical features.

Divergent Boundaries

Tectonic plate boundaries where two plates move away from each other, leading to the formation of new oceanic crust, as well as characteristic shallow earthquakes and volcanic activity due to the upwelling of magma.

Convergent Boundaries

Tectonic plate boundaries where two plates collide, resulting in the destruction of oceanic crust, the formation of deep ocean trenches, mountain ranges, and triggering significant seismic activity including deep earthquakes and volcanic eruptions.

Transform Boundaries

Tectonic plate boundaries where two plates slide past each other horizontally, known for producing significant earthquakes but not generating or destroying oceanic crust, typically characterized by shallow seismic activity.

Magnetic Stripes

Symmetrical patterns of alternating magnetic polarity found on the ocean floor, created by the periodic reversal of the Earth's magnetic field; these stripes serve as crucial evidence supporting the theory of seafloor spreading.

Hot Spots

Geological regions where volcanic activity occurs due to localized areas of intense heat in the mantle, allowing magma to penetrate the crust and create volcanoes, independent of the movements of tectonic plate boundaries.