IGNEOUS ROCKS IGNEOUS ROCKS are formed from cooled magma or lava We use COLOR & TEXTURE to classify the rocks
COLORCOLOR The COLOR of a rock depends on the rock’s mineral content The type of mineral the rock is made up of determines how it is classified
LIGHT ROCKS The rock may look light or dark Has “light” minerals LIGHT MINERALS: QUARTZ ORTHOCLASE FELDSPAR
DARK ROCKS The rock may look light or dark Has “dark” minerals DARK MINERALS: AUGITE OLIVINE
TEXTURE A rock’s TEXTURE is determined by the size of the mineral crystals within the rock Igneous Rocks have 3 basic textures
COARSE-GRAINED Has crystals large enough to be seen with the naked eye FINE-GRAINED Has crystals that are too small to see with the naked eye GLASSY Crystals are NOT visible. Glassy rocks can be smooth or full of bubble holes
vocabulary Igneous rock Rock formed from cooled magma or lava Extrusive igneous Rock Igneous rock that forms above the Earth’s surface from lava Intrusive igneous rock Igneous rock that forms below the Earth’s surface from magma
SEDIMENTARY ROCKS SEDIMENTARY ROCKS are formed from the compaction & cementation of sediments
Pressure causes accumulated sediments to harden into rock. This process takes thousands of years. Sedimentary rocks are classified according to the material from which they formed.
clastic: Composed of different sized rock fragments compacted together organic: Composed of the remains of dead plants & animals (may include shells, skeletons & other organic matter) chemical: Formed from minerals that were once dissolved in water (water evaporated & minerals became crystals)
vocabulary Sedimentaryrock Rock made of sediments Sediment Compacts together to form sedimentary rock; created by erosion compaction The compressing of sediments into sedimentary rock
erosion Wearing away of soil, landforms & rock by wind, gravity, moving water & glaciers lithification Compaction & cementation into sedimentary rock weathering The breakdown of rocks by natural processes
metamorphic ROCKS METAMORPHIC ROCKS are formed from igneous or sedimentary rocks that undergo lots of heat & pressure over a long period of time
Igneous & Sedimentary rocks deep beneath the Earth’s surface change (morph) into metamorphic rocks because of the high temperatures & great pressure of all the rock layers above. This process takes thousands of years.
2 TEXTURE TYPES NON-FOLIATED: No visible layering or stripes FOLIATED: (BANDED) Minerals “line up” to give a striped/layered appearance
vocabulary foliation Mineral bands/layers in metamorphic rock Metamorphic Rock Rock formed from an igneous or sedimentary rock because of heat & pressure
IGNEOUS ROCKS IGNEOUS ROCKS are formed from cooled magma or lava An intrusive igneous rock forms from magma. As it cools slowly inside the earth the minerals form large crystals. An extrusive igneous rock forms from lava on the surface. These rocks cool quickly and have tiny crystals.
SEDIMENTARY ROCKS SEDIMENTARY ROCKS are formed from the compaction & cementation of sediments Weathering & erosion acts upon rocks to create sediments. Over time layers of sediment compact & compress together to form sedimentary rock. This process is known as lithification.
metamorphic ROCKS METAMORPHIC ROCKS are formed from igneous or sedimentary rocks that undergo lots of heat & pressure over a long period of time, which causes the rock to change.
Rock CYCLE: The combination of all the processes that act to break down rocks, move sediments, and produce new rocks.
3 groups of rocks Igneous- Forms from cooled magma or lava Sedimentary- Made of sediments that compacted over time Metamorphic- Forms due to heat & pressure 5 processes of the rock cycle Cooling of magma or lava forms igneous rock Weathering & Erosion of a rock forms sediments Lithification of sediments forms sedimentary rock Heat & Pressure on a rock creates metamorphic rock Melting of a rock forms magma Rock CYCLE: The combination of all the processes that act to break down rocks, move sediments, and produce new rocks.