Maine Coast Geology Unit Vocabulary

Metamorphic rock

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

Foliation

Metamorphic rock texture where mineral grains are arranged in waves/bands.

Continental crust

Crust that is part of land and is often made of granite

Oceanic crust

Crust that is below the ocean and is often made of basalt.

Convergent boundary

A plate boundary where plates are moving towards each other.

Mantle

a layer of molten rock between Earth’s crust and core.

Intrusive igneous

Formed by slow-cooling magma beneath the Earth’s surface; under a volcano.

Extrusive igneous

Igneous rock formed by fast cooling magma at the surface of the Earth; at the surface of a volcano.

Sedimentary rock

Bits of dust and rock that squeeze together with pressure and compact into rock; located deep underground.

Mineral

Chemical compounds with characteristic properties that make rocks.

Quartz

Mineral that combines with feldspar to create granite

Feldspar

Mineral that combines with quartz to create granite.

Divergent boundary

A plate boundary where plates are moving away from each other.

Gneiss

Metamorphic rock with foliated layers of quartz and feldspar minerals.

Luster

How a mineral’s surface reflects light; how shiny it is.

Hardness

How easily a mineral can be scratched.

Density

How much matter is packed into a certain space; D=M/V

Streak

The color of a mineral’s powder when it is scratched on another surface.

Granite

Intrusive igneous rock with visible grains of quartz and feldspar minerals.

Basalt

Extrusive igneous rock lacking visible mineral grains.

Subduction

A convergent plate boundary where an oceanic plate is colliding and going beneath a continental plate.

Convection currents

Circulating movements of fluid in the Earth’s mantle that cause tectonic plates to move.

Magma

Molten rock beneath the Earth’s surface.

Lava

Magma that reaches the Earth’s surface during an eruption.

Solution

When one substance is dissolved in another.