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What is geology?
The study of rocks and the Earth.
What is the outermost solid layer of the Earth called?
The crust.
What is the rock cycle?
A model that explains the endless cycling of materials that make up rocks by processes within Earth and on its surface.
Where can sedimentary rocks commonly be seen?
In rivers and canyons.
What is deposition in the rock cycle?
The process by which broken rock material settles and forms sediment.
How thick is the mantle?
About 2900 km.
How thick is the crust under the oceans?
About 7 km.
Name the three main types of rocks.
Igneous rocks, sedimentary rocks, and metamorphic rocks.
How are metamorphic rocks formed?
They are changed by heat and pressure within the Earth.
What is compaction and cementation in the rock cycle?
The process by which sediment becomes packed together and chemically bound to form rock.
What is the Earth’s core mainly composed of?
Iron and nickel.
How thick is the crust under the continents?
About 30-50 km.
How do igneous rocks form?
From red hot melted rock (magma) from inside the Earth.
Where can metamorphic rocks commonly be found?
Around volcanoes and in mountain ranges.
How does melting occur in the rock cycle?
The solid rock is heated, forming magma.
Which part of the core is liquid, and which part is solid?
The outer core is liquid, and the inner core is solid.
What is the asthenosphere?
A layer within the uppermost portion of the mantle where rock behaves plastically.
Where can igneous rocks commonly be seen?
In volcanoes.
What does weathering do to rocks?
It breaks rocks down into smaller pieces.
What is crystallization?
The process by which magma becomes solid.
How does volcanic activity help to study the Earth's structure?
Volcanic eruptions provide material from deep within the Earth that helps scientists understand its structure.
What is meant by the asthenosphere behaves plastically?
It can move slowly, like plasticine.
How do sedimentary rocks form?
From small pieces worn off other rocks (sediments) becoming stuck together or when minerals in solution solidify.
What is erosion?
The transportation of broken rock material.
What does metamorphosis do to rock?
It changes the rock by intense heat and/or pressure.