Earth's Crust Flashcards

The crust is the Earth's outermost solid shell, chemically distinct from the mantle below.
The mantle lies beneath the crust, composed of silicate rocks with an average thickness of 2,886 km (1,793 mi).
Earth's core consists of an iron and nickel center, featuring a liquid outer core and a solid inner core, with the outer core starting at a depth of 2,898 km (1,800 mi) and the inner core at 4,983 km (3,090 mi).

The lithosphere encompasses the crust and uppermost mantle, forming the Earth's rigid outer layer, subdivided into tectonic plates.
The asthenosphere is part of the upper mantle, extending from about 75 km (46.5 mi) to 200 km (124 mi) deep.
The mesosphere is the layer of the Earth's atmosphere above the stratopause, where temperature decreases with altitude.

Tectonic plates are sections of the lithosphere, with seven or eight major plates and numerous minor plates on Earth.
Continental drift refers to the movement of continents relative to each other, creating the appearance of "drifting" across ocean beds.
Sea-floor spreading is the process of new ocean floor formation as molten material rises between tectonic plates.

Convergent boundaries occur when tectonic plates collide, often forming subduction zones where denser oceanic crust sinks below less dense continental or oceanic crust.
Subduction zones are regions where one tectonic plate moves under another, sinking into the mantle at convergent boundaries.
Divergent boundaries happen when two tectonic plates move apart, allowing magma to rise and create new crust. Examples include the mid-ocean ridge and the middle of the Red Sea.
Transform boundaries involve tectonic plates sliding past each other, which can cause earthquakes due to friction.

Stress is the external force exerted parallel to a slope or plane on an object or surface, leading to potential shear forces.
Compression describes the action of being pressed together or made smaller, causing changes in geological formations.