Rocks: Mineral Rocks: Mineral MixturesMixtures

• What exactly is rock? A solid mixture of minerals,

shells, bones, leaves, stems and other remains of living things.

Classify RocksClassify Rocks• The three main types of rocks are:

igneous, sedimentary, and metamorphic

• The way the rock forms or is made determines the type of rock that it is.

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Igneous RocksIgneous Rocks

• Igneous rocks were originally hot, fluid magma within the Earth.

• Igneous get their name from the Latin word, ignis, which means “fire”.

Igneous rocks are classified according where they formed.

• Extrusive rock is rock that formed from lava that erupted onto the Earth’s surface.

• Intrusive rock is rocked that formed when magma hardened beneath the Earth’s surface.

Igneous Rocks

Sedimentary RockSedimentary Rock• Most sedimentary rocks are

formed from particles that have been carried along and deposited by wind and water and then pressed together to form sedimentary rocks.

CompactionCompaction• Year after year more sediment falls on top

and are pressed to form more layers. The weight of each layer continues to compact the layers together.

Cementationthe process in which the dissolved minerals

crystallize and glue particles of sediment together

Sedimentary Rocks

Shale

Conglomerate

Sandstone

Metamorphic RocksMetamorphic Rocks

• Metamorphic rocks are new rocks that are formed when tremendous heat and great pressure change existing rocks.

• These new rocks will have chemical and physical properties that are very different from the original rocks.

Metamorphic Rocks

GneissSchist

Rock CycleRock Cycle

• The continuous changing of rocks from one kind to another over long periods of time is called the rock cycle.

• The rock cycle has no definite sequence. It can follow many different pathways.

The Value of RockThe Value of Rock• Rock is an important natural resource.• Used by early humans to make tools

such as hammers, spears, knives, and scrapers.

• Used for centuries to make buildings, roads, and monuments.

• Certain types of rocks have helped build ancient and modern civilizations.

• Rock study has helped scientists to discover the history of life on Earth.

FossilsFossils• Fossils are found in Sedimentary rock• They help provide information of life

forms that lived thousands of years ago.

Fossils provide information about life and conditions in the past.

Fossils of Sea Creatures

• Oceans once covered the area

• What part of the ocean

Fossils of Plants

• Plant fossils can tell us about the ancient environment

Animal Fossils

• Animal fossils can tell us – About past

environments– What the animal ate– How they lived