Rocks. A solid material made up of 1 or more minerals, or other things – including the remains of once-living things. Earth’s rocks are made up of about 20 minerals. A rock can have several minerals or only one. Classify Rocks. Color: color of rock depends on the minerals that make it up.
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Rocks • A solid material made up of 1 or more minerals, or other things – including the remains of once-living things.
Earth’s rocks are made up of about 20 minerals. A rock can have several minerals or only one.
Classify Rocks • Color: color of rock depends on the minerals that make it up. • Texture: size, shape, arrangement of the grains Large grains – coarse texture Small grains – fine texture
Composition: The minerals the rock is made up of • Easier to ID course grained rocks • How/where rocks are formed -
Classify Rocks 3 Major groups: Igneous Sedimentary Metamorphic
Igneous Rock http://www.fi.edu/fellows/payton/rocks/create/igneous.htm
Igneous Rock • Fire formed • Forms when magma or lava cools and hardens • Intrusive • Extrusive
Intrusive Igneous Rock • Cools and hardens beneath the surface. • Coarse grained. Larger mineral crystals. • Forms much Continental Crust. • Ex: Granite, diorite, pegmatite
Extrusive Igneous Rock • Forms from Lava on the surface of the Earth. • Fine-grained. Small Crystals Cool quickly – Basalt most common Makes up the oceanic crust. • Ex: Obsidian, pumice, andesite
Sedimentary Rock http://www.fi.edu/fellows/payton/rocks/create/sediment.htm
Sedimentary Rock • Form in places where there was once water • Form from sediment that is compacted and cemented together • Takes millions of years to form
Sediments • Particles of rock, minerals or organic material. • Sand, gravel, seashells, leaves, dead plants & animals.
Weathering - The chemical and physical processes that break down rock at Earth’s surface. • Erosion: wind, water, gravity carries sediments to a new place. • .
Deposition: when the water stops moving and “drops off” the sediments Compaction: slowly the layers of sediment press down on top of other layers
. Cementation: when the layers are “stuck” together. Water evaporates, leaving minerals behind which glue the sediments together
3 Types of Sedimentary Rock Clastic Rock: Made up of particles of pre-existing rock Can form from igneous, metamorphic or other sedimentary rocks Ex: sandstone, conglomerate
Sandstone Sedimentary, Clastic Rock Sandstone
Sedimentary, Clastic Rock Conglomerate Conglomerate
Chemical Sedimentary Rock • Form due to chemical reaction –Evaporites http://geology.campus.ad.csulb.edu/people/bperry/Sedimentary%20Rocks%20Tour/chemical_sedimentary_rocks.htm • Can occur in oceans, lakes, caves and hot springs. • Ex: limestone, halite, calcite
Limestone found in Arizona – Once part of a reef under water
Sedimentary, Chemical Rock Halite
Organic SedimentaryRock • Form when organic material – sea shells, dead animals and plant material – is compacted and cemented together • Ex: coquina, coal, anthacite
Coquina seashellsbymillhill.com 900 × 769 - Made of tiny coquina seashells
Metamorphic Rock http://www.fi.edu/fellows/payton/rocks/create/metamorph.htm
Metamorphic Rock • Meta – Change • Morph - form • Original rock – igneous, sedimentary, metamorphic – is changed by intense heat and pressure causing physical or chemical changes
Metamorphic Rock • Can form when: • rock is deep within earth’s surface – subjected to high temps and pressure of layers above • Tectonic processes – continental plates colliding • Rock is heated by molten magma nearby
Metamorphic Rock • One type of rock is changed into another type of rock • Igneous granite is changed into metamorphic gneiss • Sedimentary rock sandstone changes into quartzite
Metamorphic Rock • 2 Types: foliated and non-foliated • Foliated- banded • Examples - Gneiss, schist, slate • Non-foliated – not banded • Examples – marble, quartzite
What type of rock do I have http://www.minsocam.org/MSA/K12/rkcycle/typeofrock.html Rock cycle real pix and describe steps http://www.open2.net/geologytoolkit/rockcycle_embedded.html Good click and drag animation http://www.kscience.co.uk/animations/rock_cycle.htm Pictures of Different Rocks – Rock Picture Gallery http://geology.about.com/library/bl/images/blrockindex.htm