Lab 5 igneous rocks
Download
1 / 11

Lab 5 – Igneous Rocks - PowerPoint PPT Presentation


  • 258 Views
  • Uploaded on

Lab 5 – Igneous Rocks. Volcanic hazards Tungurahua, near Banos, Ecuador. Igneous rocks. Igneous rocks – formed from cooled molten rock Intrusive (magma) – coarse grained Extrusive (lava) – fine grained Two stages – fine grained matrix with larger crystals (phenocrysts).

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Lab 5 – Igneous Rocks' - natan


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Volcanic hazards Tungurahua, near Banos, Ecuador


Igneous rocks
Igneous rocks

  • Igneous rocks – formed from cooled molten rock

  • Intrusive (magma) – coarse grained

  • Extrusive (lava) – fine grained

  • Two stages – fine grained matrix with larger crystals (phenocrysts)


Igneous textures
Igneous Textures

  • Glassy texture – very rapid cooling of viscous lava  volcanic glass

  • Aphanitic texture – rapid cooling, ign. rocks with crystals too small to see (fine grained)

  • Phaneritic texture – slow cooling, ign. rocks with crystals that are visible (coarse grained 1-10mm)


Igneous textures1
Igneous Textures

  • Pegmatitic texture – last to cool, very course grained crystals (>1cm)

  • Porphyritic texture – represents two periods of cooling, composed of large crystals (phenocrysts) in a fine grained matrix

  • Vesicular texture – ign. rocks with vesicles in them  cause by gas bubbles being trapped in the cooling lava.


Aphanitic

Phaneritic

Glassy

Porphyritic

Vesicular

Pegmatitic


Felsic v mafic
Felsic v. Mafic

  • Felsic

    • Quartz, plagioclase feldspar, K-spar, and muscovite

    • Light in color (generally)

  • Mafic

    • Biotite, amphibole, pyroxene, and olivine

    • Dark in color (generally)



How to identify
How to Identify

  • Identify color (light/dark), but be careful!

  • Identify the minerals in the rock (if it’s not too fine grained)

  • Identify textures

  • Classify the rock using the flow chart in Fig. 5.2 and Fig. 5.3


ad