Unit 3: Plate Tectonics and Earth Structure

Environmental Earth Science Unit 3 vocabulary practice.

Asthenosphere

The layer of the Earth's upper mantle that lies directly below the rigid lithosphere, characterized by being hotter and less rigid.

Continental Crust

The crust that comprises Earth’s continents, composed mainly of granitic rock, less dense and thicker than oceanic crust.

Continental Drift

The hypothesis that Earth's continents have moved over geologic time relative to each other.

Convection Currents

Circular motions of a fluid caused by differences in density due to variations in temperature.

Convergent Boundary

An area where two or more lithospheric plates collide, resulting in one plate sliding beneath the other (subduction).

Crust

The thin outer layer of rock that forms Earth’s surface, making up about 1% of Earth's mass.

Divergent Boundary

Occurs when two tectonic plates move away from each other, leading to the creation of new crust.

Earthquake

A sudden movement of the Earth's lithosphere caused by the release of built-up stress along geologic faults.

Extrusive Rock

Igneous rock produced when magma exits and cools above or very near the Earth's surface.

Fault

A fracture in the Earth's crust where two blocks of rock have moved relative to each other.

Geosphere

The solid part of Earth, divided into crust, mantle, and core, consisting of various elements.

Hot Spot

A large plume of hot mantle material rising from deep within the Earth, resulting in volcanic activity.

Inner Core

The dense sphere of solid iron and nickel in the center of Earth, which is the hottest part.

Igneous Rock

Rock formed when hot, molten rock crystallizes and solidifies.

Intrusive Rock

Igneous rock that forms from magma trapped deep inside the Earth.

Isostasy

The concept that Earth's lithosphere floats on the fluid-like asthenosphere at an equilibrium level.

Lava

Hot molten or semifluid rock erupted from a volcano or fissure.

Lithosphere

The rigid outer part of the Earth, consisting of the crust and upper mantle.

Mantle

The layer of hot, solid material between Earth’s crust and core, making up 67% of Earth's mass.

Magma

Hot fluid material below or within the earth's crust from which lava and igneous rocks are formed.

Mesosphere

The solid lower layer of the mantle located below the asthenosphere.

Metamorphic Rock

Rock that has been substantially changed from its original igneous or sedimentary form due to heat and pressure.

Mid-Ocean Ridge (MOR)

An underwater mountain range where divergent boundaries cause seafloor spreading.

Mountain

A landform that rises at least 1,000 feet above its surrounding area.

Oceanic Crust

The crust found on the ocean floor, composed mainly of basaltic rock.

Outer Core

A fluid layer composed mostly of iron and nickel that lies above the solid inner core.

Pangaea

The last known supercontinent that existed during the late Paleozoic and early Mesozoic eras.

Plate Boundary

The border between two tectonic plates where they move and interact.

Plate Tectonics

The theory that Earth's lithosphere is broken into plates that move and interact, causing geological activity.

Rock Cycle

Describes the transitions among sedimentary, metamorphic, and igneous rock types over geologic time.

Seafloor Spreading

The process at mid-ocean ridges where new oceanic crust is formed through volcanic activity.

Sedimentary Rock

Rock formed through the deposition and solidification of sediment.

Seismic Waves

Waves of acoustic energy that travel through the Earth, often caused by earthquakes or volcanic activity.

Subduction

The sideways and downward movement of a tectonic plate into the mantle beneath another plate.

Supercontinent

A massive landmass that once encompassed most or all of Earth's continental crust.

Tectonic Plates

Massive slabs of solid rock that constitute Earth's lithosphere.

Transform Boundary

Created when tectonic plates slide past each other along strike-slip faults.

Volcano

Openings in the Earth's surface where lava and gases escape.

Tsunami

A series of ocean waves triggered by disturbances such as earthquakes or volcanic eruptions, often causing significant coastal flooding and destruction.

Oceanic Trench

A long, narrow, and deep depression on the ocean floor, typically formed at a convergent plate boundary where one oceanic plate subducts beneath another.