Rocks

8th grade Earth Science

Classifying Rocks

________________ – rocks are made of mixtures of minerals and other materials. Some contain a single mineral. Others contain several minerals.

_________ – color provides clues to the rock’s mineral composition.

(Ex: granite = light basalt = dark) _________- the look and feel of the rock’s surface.

They use shape, size and pattern. __________ – how the rock is formed.

3 Types of Rocks

There are 3 major groups of rocks:

___________________ ___________________ ___________________

Igneous Rocks

The name igneous comes from a Latin word meaning “________”.

Igneous rocks can be either __________ or ____________ rock.

_____________ – formed from lava that erupted onto the Earth’s surface.

Basalt is the most common extrusive rock. ____________– formed from magma that hardens

beneath the Earth’s surface. ____________ is the most common intrusive rock.

Igneous Rocks

Obsidian

extrusive

Granite

intrusive

Sedimentary Rocks

Sedimentary rocks are formed through a series of processes:

_______________ _______________ _______________ _______________

Sedimentary Rocks

_________ – water, wind or ice loosen and carry away fragments of rock.

__________ – sediment settles out of the water or wind carrying it.

___________ – process that presses the sediments together.

____________ – dissolved minerals crystallize and glue particles of sediment together.

Types of Sedimentary Rocks

There are 3 major groups of sedimentary rocks:

_________ – forms when rock fragments are squeezed together.

_________ – remains of plants or animals are deposited in thick layers.

_________– when minerals that are dissolved in a solution crystallize.

Sedimentary Rocks

Clastic

sandstone

Organic

coal

Chemical

limestone

Metamorphic Rocks

________ and ___________ deep beneath Earth’s surface can change any rock into metamorphic rock.

Geologists classify metamorphic rocks according to the arrangement of the ___________ that make up the rocks.

Metamorphic Rocks

There are 2 classifications for metamorphic rocks:

___________ – have their grains arranged in parallel layers or bands.

___________ – mineral grains are arranged randomly. They do not split into layers.

Metamorphic Rocks

Foliated

gneiss

Nonfoliated

quartzite

The Rock Cycle

The rock cycle is the series of processes on Earth’s surface and in the crust and mantle that slowly change rocks from one kind to another.