Environmental Science Chapter 3 - Lithosphere

geologic time scale

Earth's history organized into four eras: Precambrian, Paleozoic, Mesozoic, and Cenozoic

crust

Earth's outermost layer

core

The outer core of the Earth is a liquid layer about 2,266 km (1,408 mi) thick composed of iron and nickel which lies above the Earth's solid inner core and below its mantle. Its outer boundary lies 2,890 km (1,800 mi) beneath the Earth's surface.

plate boundaries: transform fault

a strike-slip fault occurring at the boundary between two plates of the earth's crust.

metamorphic

A type of rock that forms from an existing rock that is changed by heat, pressure, or chemical reactions.

igneous

A type of rock that forms from the cooling of molten rock at or below the surface

sedimentary

A type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together

volcano

A weak spot in the crust where magma has come to the surface

mantle

Begins about 6 miles under the ocean's crust and 19 miles below the continent's crus

subduction

A geological process in which one edge of a crustal plate is forced sideways and downward into the mantle below another plate

tsunami

A long high sea wave caused by an earthquake or other disturbance.

lithosphere

A rigid layer made up of the uppermost part of the mantle and the crust.

rock cycle

A series of processes on the surface and inside Earth that slowly changes rocks from one kind to another

asthenosphere

A subdivision of the mantle situated below the lithosphere. This zone of weak material exists below a depth of about 100 kilometers and in some regions extends as deep as 700 kilometers. The rock within this zone is easily deformed.

plate boundaries: divergent

A tectonic boundary where two plates are moving away from each other and new crust is forming from magma that rises to the Earth's surface between the two plates. The middle of the Red Sea and the mid-ocean ridge (running the length of the Atlantic Ocean) are divergent plate boundaries. Also called passive margin, spreading zone.

plate boundaries: convergent

A tectonic boundary where two plates are moving toward each other. If the two plates are of equal density, they usually push up against each other, forming a mountain chain. If they are of unequal density, one plate usually sinks beneath the other in a subduction zone. The western coast of South America and the Himalayan Mountains are convergent plate boundaries. Also called active margin, collision zone.

tectonic plates

Sections of the Earth's crust that move due to convection currents.

earthquake

Shaking and vibration at the surface of the earth resulting from underground movement along a fault plane of from volcanic activity