Rocks Oh, yeah. You rock

Sedimentary Rocks Silt Happens

Sedimentary Rocks Bedrock is solid rock under soil and sediments Sedimentary rocks are rocks made of sediments

Sedimentary Rocks Bedrock is solid rock under soil and sediments Sedimentary rocks are rocks made of sediments Sediments are carried downhill with flowing water

Sedimentary Rocks There are three types of sedimentary rock: clastic, organic, and chemical

Sedimentary Rocks Clastic sediments (clasts) are rock fragments From small to large: clay, silt, sand, pebbles

Sedimentary Rocks Clastic sediments (clasts) are rock fragments From small to large: clay, silt, sand, pebbles The larger the clast, the faster the water needs to be to move them.

Sedimentary Rocks Clastic sediments (clasts) are rock fragments From small to large: clay, silt, sand, pebbles Mudstone SiltstoneSandstone Conglomerate

Sedimentary Rocks Precipitation—solid chemicals come out of the water they were dissolved in. Chemical sedimentary rocks are formed by precipitation

Sedimentary Rocks Precipitation—solid chemicals come out of the water they were dissolved in. Chemical sedimentary rocks are formed by precipitation Rock salt (NaCl), limestone (calcite, CaCO 3 ), gypsum (CaSO 4 ), dolomite (like limestone, but with Mg) Including:

Sedimentary Rocks Organic sedimentary rocks are made from living things Ex: Coal, peat  lignite  bituminous  anthracite Some limestone is organic

Sedimentary Rocks Rocks you find now indicate conditions in the past. Limestone—oceans Sandstone—beaches (or deserts) Coal—swamps Conglomerates—base of mountains Shale—mouth of rivers Rock salt—dried up sea

Sedimentary Rocks The Earth’s climate has changed Sandstone shows dunes (or beaches) Limestone shows warm shallow ocean. Coal forms with warm climates --and is found in Antarctica!

Sediment to Rock Sediments can be formed by weathering Sediments are moved by erosion; by water, wind or gravity Sediments deposit where they are dropped Sediments are compacted by sediments on top of them Rock is cemented together (by minerals)

Sedimentary Rocks Classifying Sedimentary Rocks Look for type and size of sediments that formed it. (Clues: Color and texture)

Igneous Rocks If you can’t take the heat, stay out of the kitchen. H. S Truman

Igneous Rocks Formed from cooled magma (melted rock) Inner core Outer core Mantle Crust Mantle and outer core are melted

Igneous Rocks Parts of the crust can be melted

Igneous Rocks (Notice the ocean floor?) The most common type of igneous rock—basalt!

Igneous Rocks Magma on the surface is called lava

Igneous Rocks We will study the motion of these lithospheric plates in the next unit

Igneous Rocks (Notice the difference in the crust?)

The slower it cools, the larger the crystals grow Intrusive— cools inside the crust Extrusive— cools outside the crust Igneous Rocks

The slower it cools, the larger the crystals grow Intrusive— cools inside the crust --cools slowly Extrusive— cools outside the crust --cools fast Igneous Rocks

The slower it cools, the larger the crystals grow Intrusive— cools inside the crust --cools slowly —large crystals Extrusive— cools outside the crust --cools fast —small crystals Igneous Rocks

The slower it cools, the larger the crystals grow Intrusive— cools inside the crust --cools slowly —large crystals--rough Extrusive— cools outside the crust --cools fast —small crystals--smoother Igneous Rocks

Q: What about a rock that cools slowly for a while, then gets exposed so it cools quickly at the end?

Igneous Rocks Q: What about a rock that cools slowly for a while, then gets exposed so it cools quickly at the end? A: You get large crystals in a fine gray background

Vary in color due to the differences in the mineral content of the magma Light MineralsDark Minerals Quartz Amphibole Potassium Feldspar Biotite mica Muscovite mica Pyroxene Olivine Igneous Rocks

Magma varies depending on where it’s found Ocean Floor Continental darker colorlighter color denserlighter (less dense) thinner fluidthicker fluid less gas bubblesmore gas bubbles Igneous Rocks

Magma varies depending on where it’s found Ocean Floor Continental darker colorlighter color denserlighter (less dense) thinner fluidthicker fluid less gas bubblesmore gas bubbles Igneous Rocks More gas bubbles makes a more violent volcanic eruption!

Classified by color and texture See Table on pU20 Igneous Rocks

Classified by color and texture See Table on pU20 Igneous Rocks

Types: (By color and texture) Light and Coarse—pegmatite (and granite) Light and Medium—Granite Light and Fine—rhyolite Continental Igneous Rocks

Types: (By color and texture) Medium and Coarse—pegmatite (and diorite) Medium and Medium—Diorite Medium and Fine—Andesite (and basalt) Intermediate Igneous Rocks

Types: (By color and texture) Dark and Coarse—pegmatite (and gabbro) Dark and Medium—Gabbro Dark and Fine—Basalt Oceanic Igneous Rocks

Types: Special: Glassy—obsidian Light and Frothy—Pumice Dark and Frothy—Scoria Very Dark—peridotite Igneous Rocks

Types: Special: Glassy—obsidian Light and Frothy—Pumice Dark and Frothy—Scoria Very Dark—peridotite Igneous Rocks Continental —gas is trapped in the rock Continental—tossed into the air to cool by expanding gasses Oceanic

Elevated Landforms Castle Rock, CO Shiprock NM Mt. Cotopaxi Ecuador Pikes Peak CO Igneous rocks are tough!

Metamorphic Rock Schist Happens

Metamorphic Rock Any type of rock can be converted into metamorphic rock with enough heat and pressure IgneousSedimentary Metamorphic Heat and pressure

Metamorphic Rock (Too much heat melts the rock) Igneous Sedimentary Metamorphic Melting and cooling

The heat and pressure can: 1)Change the mineral crystals or 2)Change the minerals themselves Metamorphic Rock

The heat and pressure can: 1)Change the mineral crystals or 2)Change the minerals themselves Metamorphic Rock Metamorphism = change of form

Regional metamorphism– Contact metamorphism— Metamorphic Rock

Regional metamorphism– large parts of crust get buried or pushed deep into the Earth, then heated Contact metamorphism— new magma heats small areas of old rock Metamorphic Rock

When pressure is exerted, minerals transpose (form layers). They may even foliate (split off at these layers Metamorphic Rock Transposition Foliation

Protolith—the original rock Metamorphic Rock

Protolith—the original rock Protolith metamorphic rock Metamorphic Rock Heat and pressure

Protolith—the original rock Protolith metamorphic rock Limestone  marble Sandstone  quartzite Shale  slate Ign. & sed.  gneiss, schist, or phyllite Basalt  amphibolite Metamorphic Rock Heat and pressure

Activity 3.5 The Rock Cycle Play the game (at least 20 steps) Record your steps on the sheet Answer the questions on the back Notes to follow…

Igneous rocks are formed when any rock is melted to magma, then cooled IgneousSedimentary Metamorphic Melting and cooling

Sedimentary rocks are formed when any rock is IgneousSedimentary Metamorphic Compaction and cementation weathered and eroded, then the sediments are deposited, compacted and cemented together

IgneousSedimentary Heat and pressure Metamorphic Metamorphic rocks are formed when any rock is subjected to heat and pressure

The Rock Cycle IgneousSedimentary Heat and pressure Metamorphic Melting and cooling Compaction and cementation

The Rock Cycle IgneousSedimentary Heat and pressure Metamorphic Melting and cooling Compaction and cementation