Igneous Rocks

Igneous Rocks

1. cooling the slowest

   • magma
     • a depth within the Earth
       • coarse-grained
         • basaltic
           • gabbro
         • ultrabasic
           • peridotite
         • granitic
           • granite
         • intermediate
           • diorite
       • intrusive

2. cooling relatively slowly

   • magma
     • extremely near the surface
       • small crystal formed
         • fine-grained
           • granitic
             • rhyolite
           • intermediate
             • andesite
           • basaltic
             • basalt
         • vesicular
           • granitic/intermediate
             • pumice
           • basaltic
             • scoria
       • extrusive

3. cooling fast

   • lava
     • on the surface
       • glassy
         • crystal doesn't form at all
         • obsidian
       • extrusive

4. complex cooling history

   • cooling slowly first then suddenly fast
     • magma
       • a depth within the Earth and then move toward the surface
         • porphyritic
           • basaltic
             • porphyritic basalt or gabbro
           • intermediate
             • porphyritic andesite or diorite
           • granitic
             • porphyritic rhyolite or granite
       • intrusive (may extrusive afterward)