Journal Set up for Identification

1
Journal Set up for Identification

• In your journal, please title a page Igneous
  Rocks and draw ten of the following
  identification cards
• Other important facts
• Rock name
• Color Streak
• Texture Coarse
• Fine
• Non-existent

Sketch
2
Igneous RocksFire Rocks2 types

• Igneous rocks formed deep within the earth.
  Intrusive rocks reach the surface when the soil
  covering them is removed by erosion or when the
  forces of plate movement or earth quakes push
  them to the surface.
• Igneous rocks formed from lava at the earths
  surface. Exterior of the Earth. Holes in rocks
  are formed when gases are trapped in lava as it
  cools example pumice. No crystals are formed
  when it cools very quickly example obsidian.

• Intrusive
• Extrusive

3
Igneous RocksFire RocksFormation Facts

• 1.Texture
• 2. Chemical
• Composition
• 3. Porphyry

• Dependent on time (cooling rate) and size of
  grain
• Coarse-grained-- Slow cooling rate, large
  crystals and takes place beneath the earth
  (intrusive) example Granite(most common)
• Fine-grainedFast cooling rate, small crystals.
  Cool quickly at the surface (extrusive)
  Example Basalt (most common)
• Most igneous rocks are made of various
  combinations of six minerals quartz, feldspar,
  pyroxene, amphibole, olivine, and mica (some
  light and some dark).
• An igneous rock whose cooling rate has changed
  and has two or more different sized crystals.

4
Igneous Rocks
Intrusive (coarse grained) Extrusive (fine grained)
Light colored Granite Porphyry Rhyolite Andesite Pumice
Dark colored Gabbro Basalt Obsidian
Mixed color Diorite Andesite
5
Summary

• Studying rocks can give clues to how Earth formed
  and can explain the formation of mountains and
  other features of the earths surface. There are
  2 types of rocks formed by magma as it
  crystallizes (Igneous means that they have been
  formed by magma). Those rocks formed within earth
  are called intrusive. Those formed at the surface
  (Exterior) are called extrusive.
• There 3 important things about Igneous rocks
  formation texture of grains ( Coarse or fine)
  Chemical composition and the presence of 2
  different sized minerals (porphyry).