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EAS 332: Metamorphic Petrology 2009
Laboratory #5: The Bugaboo Contact Aureole
Battlerange Batholith, 2008 Wow this looks just like the Bugaboo !
EAS 332: Metamorphic Petrology 2009 Battlerange Batholith, 2008 Wow - - PowerPoint PPT Presentation
EAS 332: Metamorphic Petrology 2009 Battlerange Batholith, 2008 Wow - - PowerPoint PPT Presentation
EAS 332: Metamorphic Petrology 2009 Battlerange Batholith, 2008 Wow this looks just like the Bugaboo ! Laboratory #5: The Bugaboo Contact Aureole What is a contact aureole? How do you identify a contact aureole? How do you identify a
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What is a contact aureole?
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How do you identify a contact aureole?
- How do you identify a
contact aureole?
– Change in mineralogy (i.e. garnet +/- andalusite +/- cordierite +/- biotite) – Change in texture (ex: increasing grain size, massive)
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What minerals should you expect to see in this lab ?
- The rocks that are being metamorphosed are part of the
Horsethief Creek Group (which are Al-rich rocks!)
- What happens when you metamorphose an Al-rich rock? …
you get Al-rich minerals !!! (andalusite, staurolite, cordierite etc.) Sillimanite Staurolite Cordierite Andalusite
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A special note on cordierite…
- Remember this rule and your
life will be a lot easier: Cordierite is a low-rida and andalusite is a high flya ! Ok…maybe that phrase isn’t that catchy but cordierite does weather low and the other Al- rich minerals tend to be resistant to weathering and “stick out” so check out that hand specimen !!! Cordierite also commonly exhibits a special type of twinning called cyclic twinning
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A special note on sillimanite…
Remember!!! Sillimanite’s habit can range from prismatic (see above) to fibrous (see right)
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What do I need to hand in?
- Answer all of the short questions “hidden” within
the text
AND
- A full rock description of: