Rocks and Scenery ~ Rock Types ~AQA Geography

Formation: 

• MOLTEN rock from the MANTLE COOLS and SOLIDIFIES.
• Rocks formed BELOW surface in BATHOLICS = PLUTONIC or INTRUSIVE
• Rocks formed ABOVE = VOLCANIC or EXTRUSIVE

Characteristics:

• CRYSTALLINE
• Size of crystal depends on speed of solidifying
• FAST SOLIDIFYING = SMALL CRYSTALS
• SLOW SOLIDIFYING = BIGGER CRYSTALS
• Molten rock UNDERGROUND = MAGMA
• Molten rock ON THE SURFACE = LAVA

Examples:

• PLUTONIC ~ GRANITE
• VOLCANIC ~ BASALT

Formation: 

• DEBRIS is washed into RIVERS, then TRANSPORTED to the sea.
• It sinks to the BOTTOM where over MILLIONS OF YEARS sediment builds up, crushing it into rock through a process called LITHIFICATION.

Characteristics: 

• Broken down ROCKS, PLANTS, ANIMAL REMAINS
• Found in layers called STRATA
• The ONLY rock type that can contain FOSSILS

Examples:

• SANDSTONE
• LIMESTONE
• CLAYS

Formation: 

• Other rocks (eg Igneus) that have been subject to great HEAT or PRESSURE

Characteristics:

• Can be found near to VOLCANOES or MAGMA INTRUSIONS 
• HARD rocks

Examples:

• Limestone becomes MARBLE
• CLAY becomes SLATE