The Rock Cycle

Crystal Quartz

Sedimentary Rock

The Rock CycleThree Types of Rock

Igneous

Metamorphic

Sedimentary

Erosion/

Lithification

Erosion/ Lithification

Heat/ Pressure

Hea

t/

Pres

sure

Magma/ Lava

Cooling

Igneous RockFormed two ways

◦Underground Intrusive (or Plutonic) Cooling magma chambers

◦Above ground Extrusive (or Volcanic) Cooling lava

Igneous Rock

Slow cooling◦Coarse texture◦Large crystals

visible

Rapid cooling◦Fine texture◦No visible

crystals◦Sometimes

glassy◦Sometimes full

of air pockets

Cooling Rates

Igneous RockMafic Rock

◦Rich in magnesium (Mg) and iron (Fe)

Felsic Rock◦Rich in feldspar and silica (quartz)

ActivityWere they cooled rapidly or slowly?

Metamorphic Rock

Formed from Igneous and Sedimentary rock◦Changed by underground conditions (metamorphosed) Heat, pressure, and strain

Metamorphic RockRegional

MetamorphismLarge-scale Heat and

pressure work together

5- 40 km underground

Contact Metamorphism

Lava or magma in contact with rock

Dynamic Metamorphism

Pressure along fault zones

Mylonites

Metamorphic RockFoliated-Orientation of minerals is perpendicular to direction of pressure.

Non-foliated- No preferred orientation.

Sedimentary RockFormed from sediment

◦Sediment- sand, pebbles, mud, dust…

How is sediment created?◦Erosion- weathering of rock causes material to break off

Sedimentary RockLithification-

◦loose sediment is collected and hardened into rock

◦Compaction ◦Recrytallization◦Cementation

Sedimentary RockForm in beds of sediment deposition

Caused by currents, waves, drying conditions◦Ripple marks, mud cracks…

ActivityWhat type of rock is it?

ActivityWhat type of rock is it?

The Rock Cycle

Photo Sources Mike Beauregard, “Stripes”, June 2010 via flickr, Creative

Commons Attribution. Brenda Clark, “Crystal 1”, April 28,2009 via flickr, Creative

Commons Attribution. Tourist_on_earth, “Amethyst”, June 21, 2008 via flickr,

Creative Commons Attribution. Kevin Walsh, “Obsidian”, August 14, 2007 via flickr, Creative

Commoms Attribution. Siim Sepp, “Gniess”, April 20, 2005 via wikimedia, Creative

Commons Attribution. ZeWrestler, “Conglomerate Rock”, October 4, 2009 via

wikimedia, Creative Commons Attirbution. Burkina Faso, “Dry Lake”, January 2008 via wikimedia,

Creative Commons Attribution. Benjamint444, “Pumice Stone”, September 2010 via

wikimedia, Creative Commons Attribution. Peter Bockstaller, “Breccia”, 2007 via wikimedia, Creative

Commons Attribution.