rocks

• rocks

  combination of minerals that are bonded in some way
• Igneous Rocks

  -formed from hot and molten rocks that cool and harden
• Intrusive Rocks (Plutonic)


  when magma forms beneath the Earth's surface
• Extrusive Rocks (Volcanic)


  when lava solidifies at the surface
• Dark Silicate Materials

  -rich in iron/magnesium

  -low in silica
• Light Silicate Materials

  -rich in potassium, sodium, and calcium

  -rich in silica
• Granitic/Felsic

  -most abundant igneous rock
• Mafic

  -contains at least 45% dark silicate minerals

  -darker and denser because of their iron content

  -mostly found in the ocean floor
• Andesite

  -at least 25% dark silicate minerals + other minerals

  -fine grained, extrusive igneous rocks that are

  -usually light to dark gray in color
• Ultramafic

  -composed almost entirely of ferromagnesium

  -rare on Earth's surface
• faster cooling = smaller crystals

  slower cooling = larger crystals

  cools immediately = no crystals
• Types of Igneous Rocks based on the texture
• Sedimentary Rocks

  formed from pre-existing rock, minerals, and remains of living sings
• Weathering

  breaking down or dissolving of rocks
• Erosion


  process in which earthen materials are worn away and transported by natural forces
• Deposition

  laying down or dropping of a sediment in a new place by wind or water
• lithification

  process in which sediments compact under the pressure and gradually transform into solid sedimentary rocks
• Detrital

  -made up of clay minerals and quartz

  -formed from fragments of weathered rocks
• 1. Types of detrital Sedimentary Rocks based on their particle size
• Biochemical and Chemical

  -Formed from the materials that are carried to bodies of water like lakes and seas

  -The dissolved materials do not remain in the state for long and precipitate through physical processes to form
• Biochemical

  -Has a biological component

  -Formed from shells and bodies of underwater organisms
• Chemical

  -forms a crystal

  -formed from the chemical depositing of materials that were in the water
• Clastic

  consists of fragments that have been weathered, eroded, and deposited
• Non-clastic

  -from evaporated materials or from remains of animals and plants
• Organic

  -Type of sedimentary rock mostly made up of organic matter

  -Most abundant example of this is coal
• Metamorphic

  -Rocks that have “morphed” into another kind of rock.

  -Were once igneous or sedimentary rocks.

  -the rocks are under high pressure and temperature, this causes them to undergo change
• metamorphic rock formation

  -Metamorphic rocks are pre-existing rocks that have been changed by heat and/or pressure without melting.

  -These pre-existing rocks are called parent rocks.
• Contact Metamorphism

  -Smaller area

  -Involves contact of a rock with magma

  
  

  Regional Metamorphism

  -Larger area

  -Involves a collision between continental or oceanic plates
• Heat

  -Most important agent

  -Causes chemical reactions that result to the changes in the chemicalcomposition (recrystallization) of existing minerals forming new minerals
• Confining Pressure

  -As you go deeper into the Earth’s surface the pressure also increases

   -Due to the thick layer of rocks overlaying the other rocks underneath

  -Buried rocks experience confining pressure equally applied from all directions
• Differential Stress

  -Large bodies of rocks are crumpled and transformed due to unequal forces that come from dierent directions
• Foliated

  -Mineral crystals are aligned or arranged in bands or layers

  -Banding: High grade metamorphism. Alternating layers of dark andlight minerals
• Non-Foliated

  -Metamorphic rocks that do not have mineral crystals arranged in bands of layers.
• Igneous Rocks based on texture

  
• Sedimentary Rocks based on particle size

  
• Metamorphic Rocks based on texture