Rock Cycle

What makes it a rock? Rocks are solid, yes! They are also…? Crystalline made from minerals Inorganic Naturally occurring BBC Rocks & Minerals http://blogs.egu.eu/geosphere/2012/10/24/geology-photo-of-the-week-9-oct-21-27/ http://thisfortismycastle.wordpress.com/2010/02/09/awesome-rock-house/

Types of rocks

What is the rock cycle? Rock cycle: the continuous changing and remaking of rock caused by interactions with water, air, land, and living things

Igneous rocks fire form/full of ign = __________ ous = __________ rocks formed by cooling magma or lava Cooled magma = intrusive (think inside) Cooled lava = extrusive (think exit) Name two main places where igneous rock forms… Volcanoes Ridges/rifts BBC Igneous Rocks

Characteristics of igneous rocks Texture – has to do with cooling time Long cooling time = big crystals (coarse) Short cooling time = small crystals (fine) Where would you expect cooling time to be longer…above surface or below surface? Igneous Rocks

Characteristics used to classify igneous rocks texture glassy } extrusive fine

Obsidian has a glassy texture

Fine-grained igneous texture Rhyolite

Characteristics used to classify igneous rocks texture coarse } intrusive very coarse

Course-grained igneous texture Granite

Characteristics of igneous rocks (continued) Composition – what it’s made of (minerals) Judged by the amounts of light/dark materials Felsic = light colored, lots of silica, quartz, feldspar Mafic = dark colored, lots of iron, magnesium

Basalt

Granite http://kids.nationalgeographic.com/kids/photos/us-monuments/#/mount-rushmore_15118_600x450.jpg

Classification of igneous rocks

Sedimentary Rocks to settle a place for Under water! rocks formed by (1) weathering and erosion, then (2) compaction and cementation In what type of environments do most of these rocks form? Under water! BBC Sedimentary Rocks

Sedimentary rock formation Rocks are exposed to weathering and eroding -- slow wearing away of rock from wind, rain, ice Particles move to lower areas where they settle out into layers (deposition) Sediments are then compacted and cemented (lithification) Sedimentary Rocks

Sedimentary Rock Formation

Sedimentary Rocks • Compaction is a process that squeezes, or compacts, sediments. • Cementation takes place when dissolved minerals are deposited in the tiny spaces among the sediments.

3 Types of Sedimentary Rock Clastic – composed of weathered bits of rocks and minerals Classified by particle size Ex: Shale, Sandstone, Conglomerate, Grand Canyon, the Wave in Arizona

Shale with Plant Fossils Shale is formed from clay

Sandstone Sandstone is formed from sand

Conglomerate Conglomerate is formed from pebbles and other large particles

The Wave, Page, AZ

Grand Canyon, Arizona

Ayers Rock / Uluru, Australia

3 Types of Sedimentary Rock Chemical – Formed when minerals dissolve out of water Ex: rock salt, limestone (in caves) http://andbabycakesthree.blogspot.com/2011/08/salt-of-earth-maras-salt-mines-peru.html

Limestone, Carlsbad Caverns, NM Stalactites Stalagmites

3 types of sedimentary rock Organic – formed by fossils or organic matter within the rock layers Ex: coal, oil shale, some limestone (shells,)

Fossiliferous Limestone Formed from animal shells

Anthracite Coal Formed from ancient swamp plants

Classification of Sedimentary Rocks

Metamorphic Rocks to change form Rocks changed by great heat and pressure in the crust and upper mantle NOT hot enough to melt the rock (which would make it igneous) Rock it comes from is called “parent rock” Parent rock Metamorphic rock

Agents of Metamorphism Metamorphic Rocks Agents of Metamorphism Heat – provides the energy to drive chemical changes Pressure – causes a more compact rock with greater density Can cause unique folding and deformity

Where do metamorphic rocks form? BBC Metamorphic Rocks Form at plate collisions Form when magma contacts existing rock Form at great depths

2 types of metamorphic rock Foliated – looks banded or layered the folds show the direction pressure was applied Nonfoliated – does not look banded or layered Amphibolite Gneiss

Slate shows distinct layers Texting in the Old Days….

Mica is also foliated

Marble — a nonfoliated metamorphic rock

Classification of Metamorphic Rocks