http://www.learner.org/interactives/rockcycle/

Catherine M.

A group of processes through which Earth materials may pass

as they are transformed from one major rock type to another.

Three Major Rock Types

http://www.windows.ucar.edu/tour/link=/earth/geology/rock_cycle.html

• Uplift and Magma dispersement

• Weathering and Erosion

• Deposition of material

• Sedimentary Rock is created

• Heat + Pressure + Time = Metamorphic Rock

• More Heat + Pressure = Igneous Rock

Sedimentary rock is formed when sediment comes together and bonds either by compaction, cementation or both.

There are three types of sedimentary rocks:

Clastic – formed by mechanical weathering debrisChemical – formed by dissolved materials in a solutionOrganic – accumulation of plant or animal debris

Each type of sedimentary rock has its own distinct composition, color and texture.

Sedimentary rock is the only place where we find fossils.

Quartz Sandstone

http://csmres.jmu.edu/geollab/fichter/SedRx/SimpModl.html

Shelf Shale (Clay)

Limestone (crushed shell)

Breccia - Clastic Coal - Organic

Conglomerate - Clastic

Iron Ore - Chemical

                                                                          

Rock Salt - ChemicalSandstone - Castic

http://geology.com/rocks/sedimentary-rocks.shtml

Metamorphic rock is any rock that has been changed from its original condition by heat, pressure and the chemical activity of fluids, as in marble and slate.

This change usually occurs under the Earth’s surface and when conditions are right, heat and pressure cause the mineral composition and/or texture to transform the original rock into a newly formed rock.

http://www.windows.ucar.edu/tour/link=/earth/geology/meta_intro.html

• Rocks that are in contact with hot magma or lava often become metamorphosed. This is called contact metamorphism.

• Contact metamorphism can either happen deep underground or at the Earth's surface. Underground, hot magma, fills areas within the crust; large areas are called batholiths. The hot magma alters the surrounding rocks. The amount of rock that is changed depends on how much magma there is producing heat.

• Above ground, lava erupting from a volcano alters the rock that it erupts onto.

http://www.windows.ucar.edu/tour/link=/earth/geology/meta_contact.html

• Sometimes rocks are metamorphosed over large areas that are the size of many states or even several countries. This is called regional metamorphism.

• Pieces of the Earth's surface layer (called the lithosphere) crash into each other, rocks are squished and changed deep within mountain ranges. This type of process happens along convergent boundaries.

• One piece of the lithosphere is pulled below another and the rocks are altered deep underground by the high pressure and temperature. This type of process is referred to as Subduction.

http://www.windows.ucar.edu/tour/link=/earth/geology/meta_regional.html

Slate

Quartzite

Gneiss

Hornfels

Marble

Garnet Schist Schist (Muscovite)

• Igneous rocks are divided into two groups, based on where the rock forms.

• Intrusive igneous rocks are formed inside the Earth and extrusive igneous rock are formed when they cool on the surface.

Soufriere Hills, Montserrat

http://volcano.und.edu/vwintl/vwintl.html

• Many kilometers below the Earth’s surface, molten rock called magma flows into cracks or underground chambers. There, the magma sits, cooling very slowly over thousands to millions of years. As it cools, elements combine to form common silicate minerals, the building blocks of igneous rocks. These mineral crystals can grow quite large if space allows and can be seen with the naked eye.

• There are many different types of intrusive igneous rocks but granite is the most common type.

http://www.windows.ucar.edu/tour/link=/earth/geology/ig_intrusive.html

http://www.beg.utexas.edu/mainweb/publications/graphics/granite-400.jpg

GraniteGabbro

Pegmatite

http://geology.com/rocks/igneous-rocks.shtml (2)

http://www.windows.ucar.edu/tour/link=/earth/geology/ig_extrusive.html

The molten rock (magma) erupts or flows above the surface as lava, and then cools

forming rock. When lava erupts onto the Earth's surface, it cools quickly. If the lava cools in less than a day or two, there is no time for elements to form minerals. Instead, elements are frozen in place within volcanic glass. Often, lava

cools over a few days to weeks and minerals have enough time to form but not time to

grow into large crystals. Basalt is the most common type of extrusive

igneous rock and the most common rock type at the Earth's surface.

Stromboli, Italy

Basalt Obsidian

Scoria

Pumice Welded Tuff

http://geology.com/rocks/igneous-rocks.shtml

http://www.msnucleus.org/membership/html/k-6/rc/rocks/6/rcr6_2a.html