Rocks & The Rock Cycle

Take it one step at a time.

The Earth Core = magma (molten rock) Outside = solid rock Magma kept hot by nuclear reactions.

Getting To The Surface MAGMA

Volcanoes MAGMA IGNEOUS ROCK Quick Cooling Extrusive

Cooling Underground MAGMA Slow Cooling Intrusive

Cooling Off Slow cooling Crystals have time to grow Fast cooling No time to grow crystals Can get single metal crystals. Can get metallic glass – talk about ribbons. Glass is a liquid – no structure. INTRUSIVE IGNEOUS EXTRUSIVE IGNEOUS

Weathering & Erosion BIG ROCKS lots of little rocks

Little Rocks

Sedimentary Rocks Suspension Sedimentation Can also be little bits of coral, sea shells, etc. Compression causes mineral salts to cement rock together Oldest layer at the bottom. Rock forms under compression

THIS TAKES MILLIONS OF YEARS!!! Fossils THIS TAKES MILLIONS OF YEARS!!! Animal will be squashed.

Pushed, Shoved, And Heated PRESSURE FROM MOVEMENTS IN THE CRUST METAMORPHIC Changes structure Ceramic pots Marble as the metamorphic version of chalk HEAT

The Rock Cycle Revisited

Rocks and the rock cycle The rock cycle is a set of processes through which different kinds of rocks are formed and change into each other. The three main kinds of rock are: Igneous (Intrusive & Extrusive) Sedimentary Metamorphic Powering the rock cycle is magma (molten rock), and the movement of the tectonic plates (continental plates) on the Earth’s crust.

Igneous rocks Igneous rocks are formed by the cooling of magma. Magma can cool quickly, during a volcanic eruption, forming extrusive igneous rocks which have small crystals or are glassy. Magma can cool slowly underground, forming intrusive igneous rocks, which have large crystals.

Sedimentary rocks Rocks get weathered and broken into small pieces. They are then washed to the sea, where they form a suspension. The suspension of rock particles settles on the sea bed, forming a layer of sediment. Layers of sediment build on top of each other, squeezing the bottom layer with their weight. Under this pressure, the sediment sticks together and forms sedimentary rocks.

Metamorphic rocks Sedimentary rocks and metamorphic rocks are squeezed underground by movements in the Earth’s crust. The combination of pressure (from squeezing), and heat (from being close to magma) causes these rocks to change structure, turning into metamorphic rocks.